Question

The sides of a triangle are 3 cm, 4 cm, and 5 cm in length. Find the greatest angle of this triangle.

Answer 1

Given, sides of the triangle are 3 cm, 4 cm and 5 cm.

We have $3^2+4^2=9+16=25=5^2$

By the converse of Pythagoras' theorem, if in a triangle, the square of one side equals the sum of squares of the remaining two sides, then the triangle is right-angled.

Thus, the given triangle is right-angled and hence, its greatest angle is ${90}^{\circ }$