The base of an isosceles triangle is 30 cm and the lateral side is 25 cm. Calculate the height drawn to the base.

The height drawn to the base of the isosceles triangle is the median and bisects the base.

Side b, half of the base a and height h drawn to it form a right-angled triangle. By the Pythagorean theorem:

a ^ 2 + h ^ 2 = b ^ 2;

h ^ 2 = b ^ 2 – a ^ 2 = 25 ^ 2 – 15 ^ 2 = 625 – 225 = 400;

h = √400 = 20 cm – the height drawn to the base of this isosceles triangle.