Question

The Length of a rectangle is 5 centimeters less than twice its width . The perimeter of the rectangle is 80cm. What are the dimensions of the rectangle ?

Answer 1

Perimeter is the sum of all a shapes sides.

with that in mind, we know a rectangle has four sides. with 2 pairs being the same.

The length as told is, 5 centimeters less than two times the width. Two times the width would be 2w and five less than that would be minus five. so the length is 2w - 5

now to find the perimeter we do two times the width + two times the length.

2w + 2(2w -5) = 80.
Distribute: 2w + 4w - 10 = 80
Add ten to both sides and combine the 2w & 4w:
6w = 90
Divide both sides by 6: w = 15.

with this we know the width is 15. to find length plug in 15 to the 2w - 5 equation.

2(15) - 5 = 30 - 5 = 25.

Slap on the units and width = 15 cm, length = 25 cm