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

length = 25 cm; width = 15 cm
length = 22 cm; width = 18 cm
length = 24 cm; width = 16 cm
length = 23 cm; width = 14 cm

Respuesta :

caylus
Hello,

Answer A
Let's the width of the rectangle

2a-5 its length
Teh half perimeter is 80/2=40
a+2a-5=40 ==>3a=45==>a=15 and 2a-5=30-5=25


Answer:

Length = 25 cm , Width = 15 cm.

Step-by-step explanation:

Given  : The length of a rectangle is 5 centimeters less than twice its width. The perimeter of the rectangle is 80 cm.

To find : What are the dimensions of the rectangle.

Solution : We have given

Perimeter = 80 cm .

According to question :

Let width of rectangle = W .

Length is  twice its width.

L = 2W .

Length of a rectangle is 5 centimeters less than twice its width.

L = 2W - 5.

Then ,

Perimeter = 2 ( length + width).

Plug the values

80 = 2 ( 2W - 5 + W ) .

80 = 2( 3W -5) .

On dividing both sides by  2

40 = 3W - 5 .

On adding both sides by 5.

45 = 3 W .

On dividing both sides by 3.

W = 15 cm .

L = 2W -  5.

L = 2 ( 15) - 5 .

L = 30 -5 .

L = 25 cm .

Therefore, Length = 25 cm , Width = 15 cm.