Question

a rectangle has a perimeter 20m. express the area of the rectangle as a function of the length of one of its sides.

Answer 1

Let L, H be the length and the height of the rectangle.
So the perimeter is 2L+2H = 20
i.e. L+H=10
=> H = 10 - L
Area of the rectangle given by L X H
You can substitute H in above equation to find the area in terms of L