Find the length of a rectangle if its
width is 13 less than the length and its
perimeter is 90 cm.
( im desperate ty)

L = 29cm

Step-by-step explanation:

Let's go!!

To find any rectangle area, you have to apply this formula: A = L . w , where L is the length and w is the width.

So, we have w = L - 13 (the width is 13 less than the Length) and then, perimeter is 90 cm.

Well, I hope you remember that the perimeter of rectangle is 2L + 2W. In this case, 2L + 2w = 90

Then, you might to solve this system of equation:

2L + 2w = 90

w = L - 13

Simplifying the first equation, you'll have L + w = 45 (you can divide everything of 2).

Our new system:

L + w = 45

w = L - 13

Using the substituition method:

L + L - 13 = 45

2L = 58

L = 29 cm

the width is 29 - 13 = 16 cm

step-by-step explanation: