Question

The sides of a triangle measure 15 cm, 36 cm and 39 cm. Show that it is a right-angled triangle.

Answer 1

The largest side of the triangle is 39 cm.

$$\begin{gathered} {15}^2+{36}^2 \\ =225+1296=1521 \end{gathered}$$

Also, ${39}^2=1521$
∴ ${15}^2+{36}^2={39}^2$

Sum of the square of the two sides is equal to the square of the third side.

Hence, the triangle is right angled.