Question

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

Answer 1

In $△ABC$ sides AB= 13cm , AC=13cm

let M be a point on side BC

Such that BM = a ,MC = a

AMC is a right angle triangle at M...

By pythagoras theorem

$A{M}^2+M{C}^2=A{C}^2$

$5^2+a^2={13}^2$

$a^2=169-25=144$

$a^2=144$

a=12

BC = AM + MC = a + a = 12 + 12 = 24

BC = 24