Question

A greeting card has an area 90 cm². Between what two whole numbers is the length of its side?

Answer 1

1	90
5	45
3	9
3	3
	1

Area of the greeting card = 90 cm²

(side)² = 90 cm²

(side)² = 2 × 5 × 3 × 3 = 2 × 5 × 3² 

`sqrt(("side")^2) = sqrt(2 xx 5 xx 3^2)`

side = `3sqrt(2 xx 5)`

side = `3sqrt(10)` cm

side = 3 × 3.2 cm

side = 9.6 cm

∴ Side lies between the whole numbers 9 and 10.