Question

What is the length of the longest side of a right-angled triangle whose other two sides are 8 m and 15 m long?

• A. 12 m
• B. 7 m
• C. 17 m
• D. 289 m

Answer 1

The correct option is C 17 m

In a right-angled triangle, the longest side is its hypotenuse.
Also, in such a triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
$\therefore$ Using Pythagoras' Theorem, we get that the hypotenuse equals $\sqrt{{15}^2+8^2}.$
$\Rightarrow \text{Hypotenuse}=\sqrt{225+64}$ $=\sqrt{289}$
$=17\text{m}$

Therefore, the length of the hypotenuse is 17 m.