In the right-angled triangle shown in the figure, if AB = 4 cm and AC = 5 cm, then BC = ?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 3 cm
The right angle is at B, so AC, the side opposite it, is the hypotenuse. By Pythagoras’ theorem, \(AC^2=AB^2+BC^2\).
\(BC^2=AC^2-AB^2=5^2-4^2=25-16=9\)
BC is a length, so take the positive root: \(BC=3\) cm