Work out the area of a rectangle with base, b =
18mm and perimeter, P = 60mm.
b b

Area of rectangle = 216 square mm

Step-by-step explanation:

Base (b ) = 18 mm

width = 'x' mm

Perimeter of rectangle = 2*(base + width)

Perimeter = 60 mm

2*(base + width) = 60 mm

2 *(18 + x )  = 60

2*18 + 2*x = 60

36   + 2x  = 60

         2x = 60 - 36

         2x = 24

          x = 24/2

    x = 12

Width = 12 mm

Area of rectangle = base * width

                             = 18 * 12

                             = 216 square mm