Perimeter of a rectangle

The perimeter of a rectangle is the sum of the lengths of all of its sides:

P = 2l + 2w

where P is perimeter, l is length, and w is width.

Example:

Find the perimeter of the tennis court with a length of 78 feet and width of 27 feet.


P =2l + 2w
=2 × 78 + 2 × 27
=210 feet

Example:

Find the perimeter of rectangle whose length is twice the size of its width, and has a diagonal of 10.


The diagonal divides the rectangle into two congruent right triangles. Using the Pythagorean theorem, we can find w:

w2 + (2w)2 = 102

w2 = 20

w = 2


P =2l + 2w
=2(2w) + 2w
=6w
=
=