Triangle ABC has perimeter 22 cm. AB = 8cm BC=5cm By calculation deduce whether triangle ABC is a right-angled triangle.

The perimeter is 22cm therefore the remaining side is 22-8-5=9 cm. A right triangle follows the Pythagorean theorem which states that any side is equal to the square root of the sum of the squares of the other side or A=B2+C2. Using this we can get side AB and see if we can get it using the Pythagorean theorem. 52+92=10.30 cm. therefore, triangle ABC is not a right-angled triangle