Question

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

• A. ${180}^{\circ }$
• B. ${90}^{\circ }$
• C. ${45}^{\circ }$
• D. ${100}^{\circ }$

Answer 1

The correct option is B ${90}^{\circ }$

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 ${90}^{\circ }$