Question

An isosceles triangle has congruent sides of 20 cm. The base is 10 cm. Find the length of the triangle.

Answer 1

if we draw a line from the vertex to the midpoint of the base we get 2 right angled triangles. So we can use Pythagoras theorem to find the length ( height):-

20^2 = x^ + 5^2
x^2 = 400 - 25 = 375
x = sqrt 375 = 19.36 cm to nearest hundredth.