Question

Each of the small shaded squares inside the

rectangle below has an area of 9 cm².
What area of the rectangle is unshaded?
Give your answer in cm².

Answer 1

279 cm²

Explanation:

You want the unshaded area in a rectangle occupied by a number of shaded squares that are each 9 cm².

Size

By counting squares, we see the rectangle is 6 squares wide and 8 squares high, so has an area of 6·8 = 48 squares.

By counting squares, we see that there are 17 shaded squares. That leaves an unshaded area of ...

48 -17 = 31 . . . squares

Area

The area of each of the squares is 9 cm², so the area of 31 of them is ...

unshaded area = 31 · 9 cm² = 279 cm²