What are the perimeter and area of a rectangle with a length of 20in and a width of 15 in

The equation for the area of a rectangle is: A = lw, where l=length and w=width. 
The perimeter of a rectangle is the sum of all the sides of the rectangle. The equation for the perimeter is: P = 2(l+w), where l=length and w=width.

You know that length, l = 20in, and width, w = 15in. So put those values into the equations:
1) Area of the rectangle:
A = lw
A = (20 in)(15 in)
A = 300

2) Perimeter of the rectangle:
P = 2(l+w)
P = 2(20in + 15in)
P = 2(35in)
P = 70 in.

The area of the rectangle is 300  and the perimeter is 70 in.