1. Problem: Determine if the triangle with sides 40 cm, 8 cm, and 41 cm is right angled. Use the Pythagorean theorem: $$a^2 + b^2 = c^2$$ where $c$ is the longest side. Calculate: $$40^2 + 8^2 = 1600 + 64 = 1664$$ Calculate: $$41^2 = 1681$$ Since $$1664 \neq 1681$$, the triangle is not right angled. 2. Problem: Determine if the triangle with sides 65 cm, 52 cm, and 39 cm is right angled. Longest side is 65 cm. Calculate: $$52^2 + 39^2 = 2704 + 1521 = 4225$$ Calculate: $$65^2 = 4225$$ Since $$4225 = 4225$$, the triangle is right angled. 3. Problem: Determine if the triangle with sides 65 cm, 58 cm, and 28 cm is right angled. Longest side is 65 cm. Calculate: $$58^2 + 28^2 = 3364 + 784 = 4148$$ Calculate: $$65^2 = 4225$$ Since $$4148 \neq 4225$$, the triangle is not right angled. Final answers: (a) Not right angled (b) Right angled (c) Not right angled