Geometry - Pre-Algebra
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What is the circumference of a circle with a radius equal to 
?
What is the circumference of a circle with a radius equal to
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The circumference can be solved using the following equation:
The circumference can be solved using the following equation:
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The perimeter of a given rectangle is equal to the circumference of a given circle. The circle has radius 
inches; the width of the rectangle is 
inches. What is the length of the rectangle?
The perimeter of a given rectangle is equal to the circumference of a given circle. The circle has radius
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The circumference of a circle with radius 
inches is
inches.
The perimeter of the rectangle is therefore 
inches. To find its length, substitute 
and 
into the equation and solve for 
:
inches
The circumference of a circle with radius
The perimeter of the rectangle is therefore
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What is the circumference of a circle with an area equal to 
?
What is the circumference of a circle with an area equal to
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Using the area, solve for the radius:
Divide by 
:
Take the square root:
Plug this radius into the formula for the circumference:
Using the area, solve for the radius:
Divide by
Take the square root:
Plug this radius into the formula for the circumference:
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Becky's house is surrounded by a circular lake that Becky runs around each day. If Becky wants to figure out the distance she runs around the lake, what formula should Becky use?
Becky's house is surrounded by a circular lake that Becky runs around each day. If Becky wants to figure out the distance she runs around the lake, what formula should Becky use?
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Becky should use the circumfrence formula to find the distance she runs of a lake.
Correct Answer: 
Becky should use the circumfrence formula to find the distance she runs of a lake.
Correct Answer:
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What is the circumference of a circle with a radius of 
?
What is the circumference of a circle with a radius of
Tap to reveal answer
The circumference can be solved using the following equation:
Where 
represents the radius. Therefore, when we substitute our radius in we get:
The circumference can be solved using the following equation:
Where
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Determine the circumference of the circle if the radius is 20.
Determine the circumference of the circle if the radius is 20.
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Write the formula for circumference.
Substitute the radius and solve.
Write the formula for circumference.
Substitute the radius and solve.
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Given the area of the circle is 
, what is the circumference of the circle?
Given the area of the circle is
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Write the formula for the area of a circle.
Substitute the area.
Write the circumference of the circle.
Substitute the radius.
Write the formula for the area of a circle.
Substitute the area.
Write the circumference of the circle.
Substitute the radius.
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Find the circumference of the circle with a diameter of 
.
Find the circumference of the circle with a diameter of
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Write the formula for the circumference of a circle.
Substitute the diameter.
Write the formula for the circumference of a circle.
Substitute the diameter.
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Find the circumference of a circle with an area of 
.
Find the circumference of a circle with an area of
Tap to reveal answer
Write the area formula in order to find the radius.
Substitute the area.
Write the circumference formula.
Substitute the radius.
Write the area formula in order to find the radius.
Substitute the area.
Write the circumference formula.
Substitute the radius.
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Determine the circumference of the circle if the radius is 
.
Determine the circumference of the circle if the radius is
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Write the formula for the circumference of a circle.
Substitute the radius into the formula.
Write the formula for the circumference of a circle.
Substitute the radius into the formula.
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Find the circumference of a circle with a radius of 
.
Find the circumference of a circle with a radius of
Tap to reveal answer
Write the formula to find the circumference of a circle.
Substitute the radius.
Write the formula to find the circumference of a circle.
Substitute the radius.
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Find the circumference of a circle with an area of 5.
Find the circumference of a circle with an area of 5.
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Write the formula for the area of a circle.
Substitute the area to find the radius.
In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.
Write the formula to find the circumference of the circle.
Substitute the radius.
Write the formula for the area of a circle.
Substitute the area to find the radius.
In order to solve the equation, we have to isolate the variable. We do this by performing the same operation to either side of the equation.
Write the formula to find the circumference of the circle.
Substitute the radius.
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If 
find the circumference of a circle with a diameter of 10 inches.
If
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To solve, we will use the formula for circumference of a circle. The formula is
where 
. We know that the diameter of the circle is 10 inches. To find the radius, we simply divide by 2.
Therefore,
We know 
, so we will substitute. We get
Therefore, the circumference of the circle is 31.4 inches.
To solve, we will use the formula for circumference of a circle. The formula is
where
Therefore,
We know
Therefore, the circumference of the circle is 31.4 inches.
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Find the circumference of a circle with a radius of 6cm.
Find the circumference of a circle with a radius of 6cm.
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The formula to find the circumference of a circle is
where d is the diameter. We know the radius is 6cm. We also know to find the diameter, we take two times the radius. Therefore, the diameter is 12cm. So, substituting into the formula, we get
or
Therefore, the circumference of the cirlce is 
.
The formula to find the circumference of a circle is
where d is the diameter. We know the radius is 6cm. We also know to find the diameter, we take two times the radius. Therefore, the diameter is 12cm. So, substituting into the formula, we get
or
Therefore, the circumference of the cirlce is
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A circle has a radius of 
. What is its circumference?
A circle has a radius of
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The formula for the circumference of a circle is
.
So, we simply plug in the radius of 
in order to solve for the circle's circumference:
Therefore, the circumference of ths circle is 
.
The formula for the circumference of a circle is
So, we simply plug in the radius of
Therefore, the circumference of ths circle is
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What is the distance around a silo, if the distance from the center of the silo to the outside is 
?
What is the distance around a silo, if the distance from the center of the silo to the outside is
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What is the distance around a silo, if the distance from the center of the silo to the outside is 
?
Picture a silo, its base is a circle.
This problem want the circumference of that circle. It gives us the distance from the center to the outside of the circle, aka the radius.
Find circumference via the following formula:
So the distance is:
What is the distance around a silo, if the distance from the center of the silo to the outside is
Picture a silo, its base is a circle.
This problem want the circumference of that circle. It gives us the distance from the center to the outside of the circle, aka the radius.
Find circumference via the following formula:
So the distance is:
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Alfredo ran laps around his track. He had just learned in math about circumference and was wondering what the circumference of his circular track was. He knows that the diameter of his track is 100 feet. What is the circumference of Alfredo's track?
Alfredo ran laps around his track. He had just learned in math about circumference and was wondering what the circumference of his circular track was. He knows that the diameter of his track is 100 feet. What is the circumference of Alfredo's track?
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The only thing that needs to be known for this question is the equation for circumference which is:
Therefore your answer to this problem is simply
The only thing that needs to be known for this question is the equation for circumference which is:
Therefore your answer to this problem is simply
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Michelle wants to put a fence up around all four sides of her rectangular garden, which measures 10 ft. long and 15 ft. wide. How long will her fence be?
Michelle wants to put a fence up around all four sides of her rectangular garden, which measures 10 ft. long and 15 ft. wide. How long will her fence be?
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Since the perimeter marks out the distance around a shape, you can imagine yourself walking around a shape to find the perimeter. For a rectangle, you would walk the same length twice (once on each side) and the same width twice (once on each side). That's why you multiply both the length and the width by 2.
To find the perimeter, use the following formula:
Step 1: insert length and width into the formula
Step 2: solve
Since the perimeter marks out the distance around a shape, you can imagine yourself walking around a shape to find the perimeter. For a rectangle, you would walk the same length twice (once on each side) and the same width twice (once on each side). That's why you multiply both the length and the width by 2.
To find the perimeter, use the following formula:
Step 1: insert length and width into the formula
Step 2: solve
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Susy's yard is 32 yards by 17 yards. What is the total perimeter of her yard?
Susy's yard is 32 yards by 17 yards. What is the total perimeter of her yard?
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Recall, the perimeter of a rectangle = 2*length + 2*width
Using the values given to us in the problem:
Thus, the perimeter is 98 yards.
Recall, the perimeter of a rectangle = 2*length + 2*width
Using the values given to us in the problem:
Thus, the perimeter is 98 yards.
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Sally has a rectangular garden that is surrounded by a 6ft-wide and 8ft-long fence. However, she wants to expand her garden so that it is twice as wide and twice as long. What is the new perimeter of her garden?
Sally has a rectangular garden that is surrounded by a 6ft-wide and 8ft-long fence. However, she wants to expand her garden so that it is twice as wide and twice as long. What is the new perimeter of her garden?
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We know the original garden is a 6ft by 8ft rectangle. sally wants to expand her garden so that the new rectangle is twice as long and twice as wide, so the new dimensions are 12ft by 16ft.
The perimeter of a rectangle with these dimensions is
12*2 +16*2 = 56.
We know the original garden is a 6ft by 8ft rectangle. sally wants to expand her garden so that the new rectangle is twice as long and twice as wide, so the new dimensions are 12ft by 16ft.
The perimeter of a rectangle with these dimensions is
12*2 +16*2 = 56.
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