Question

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

Answer 1

Answer:

No, its not a right angle triangle. check for explanation below ↓

In order to figure whether ABC is a right-angled triangle.

First find the missing side:

22 - 8 - 5

9 cm

so the sides are 5 cm, 8 cm, 9 cm

using the rule:

short side² + short side² = biggest side²

5² + 8² = 9²

25 + 64 = 81

89 = 81

Thus found ABC is not a right-angled triangle.

Answer 2

$AC = 22 - (8+5) = 22 - 13 = 9$

$9^2 + 13^2 = 81 +169 = 250$

$22^2 = 484$

So no, ABC is NOT a right triangle because the pythagorean thoerem fails