Question

Find the third side in the given triangle. Name the theorem used to find the third side. What are such triangles called? [3 MARKS]

Answer 1

Name: 1 Mark
Theorem: 1 Mark
Answer: 1 Mark

Since $\angle C$ is ${90}^{\circ }$, the following is a right-angled triangle.
The theorem used is known as Pythagoras Theorem.
In a right angled triangle,
Base${}^2$ + perpendicular${}^2$ = hypotenuse${}^2$ (Pythagaros's Theorem)
Or, AB${}^2$ = BC${}^2$ + AC${}^2$
Or, AB${}^2$ = 16 + 9 = 25
Or, AB = $\sqrt{25}$ = 5