How to find the perimeter of the rectangle

A rectangular postage stamp has a width of 3 cm and a height of 12 cm. Find the perimeter of the stamp.

To find the perimeter of a rectangle (or any shape) simply add up all the sides.

In this case, we have two sides that are 3 cm and two sides that are 12 cm.

Now, our answer must be in centimeters and not centimeters squared, because we are dealing with perimeter, which is a measure of length.

To find the perimeter of a rectangle, we will use the following formula:

where a, b, c, and d are the lengths of the sides of the rectangle.

Now, let's look at the rectangle.

We can see the length is 9 inches. Because it is a rectangle, the opposite side is also 9 inches. We can see the width is 6 inches. Because it is a rectangle, the opposite side is also 6 inches.

Knowing this, we can substitute into the formula. We get

To find the perimeter of a rectangle, we will use the following formula:

Where a, b, c, and d are the lengths of the sides of the rectangle.

Now, we know the length of the rectangle is 12cm. Because it is a rectangle, the opposite side is also 12cm. We also know the width of the rectangle is a quarter of the length. To find the width, we will divide 12 by 4. Therefore, the width is 3cm. Because it is a rectangle, the opposite side is also 3cm.

Knowing this, we can substitute into the formula. We get

To find the perimeter of a rectangle, we will use the following formula:

Where a, b, c, and d are the lengths of the sides of the rectangle.

Now, we know the length of the rectangle is 16cm. Because it is a rectangle, the opposite side is also 16cm. We also know the width of the rectangle is a quarter of the length. To find the width, we will divide 16 by 4. Therefore, the width is 4cm. Because it is a rectangle, the opposite side is also 4cm.

Knowing this, we can substitute into the formula. We get

Opposite sides of a rectangle are congruent.

The large rectangle has perimeter

.

The smaller rectangle has perimeter

.

The ratio is

; that is, 12 to 5.

The perimeter of the rectangle is yards. To convert this to centimeters, multiply by the given conversion factor:

centimeters.

To find the perimeter of a rectangle, we will use the following formula:

Where a, b, c, and d are the lengths of the sides of the rectangle.

Now, we know the width of the rectangle is 7in. Because it is a rectangle, the opposite side is also 7in.

We know the length is two times the width. Therefore, the length is 14in. Because it is a rectangle, the opposite side is also 14in.

Knowing this, we can substitute into the formula. We get

To find the perimeter of a rectangle, we will use the following formula:

where a, b, c, and d are the lengths of the sides of the rectangle.

Now, we know the length of the rectangle is 7in. Because it is a rectangle, the opposite side is also 7in.

We also know the width of the rectangle is 4in. Because it is a rectangle, the opposite side is also 4in.

Knowing this, we can substitute into the formula. We get

To find the perimeter of a rectangle, we will use the following formula:

where a, b, c, and d are the lengths of the sides of the rectangle.

Now, we know the width of the rectangle is 8cm. Because it is a rectangle, we know the opposite side is also 8cm. We also know the length is three times the width. Therefore, the length is 24cm. Because it is a rectangle, we know the opposite side is also 24cm.

Knowing all of this, we can substitute into the formula. We get

Since opposite sides of a rectangle have the same measure, the missing sidelengths can be calculated as in the diagram below:

The sidelengths of the red polygon can now be added to find the perimeter: