Practice!

Sample Problem

The area of the small square is 1 cm 2. The widths of the corridors are 1cm. So the area of square ABCD is ___ cm 2.

Solution

ABCD can be divided into small squares which equal to the given square. AD is 9 times the side length of the small square and is the same as AB. So ABCD is 9 × 9 = 81 cm 2.