Question

∆ABC is an isosceles triangle with AB = AC = 13cm. The length of altitude from A on BC is 5cm. Find BC.

Answer 1

It is given that ∆ ABC is an isosceles triangle. 

Also, AB = AC = 13 cm

Suppose the altitude from A on BC meets BC at D. Therefore, D is the midpoint of BC. 

AD = 5 cm 

∆ ∆ are right-angled triangles. 

Applying Pythagoras theorem, we have;

Hence, 

BC = 2(BD) = 2 × 12 = 24 cm