Question

Given AB=10cm, CD=11cm, and AD=39cm, find the length of BC

Answer 1

BC = 18 cm

Explanation:

As we can see from the diagram:

AB + BC + CD = AD

⇒ 10 cm + BC + 11 cm = 39 cm

⇒ BC + 21 cm = 39 cm

⇒ BC = 39 cm - 21 cm

⇒ BC = 18 cm