Concept:Use Pythagoras' theorem for a right-angled triangle.Explanation:The side opposite the right angle is the hypotenuse, which is 13.So, 52+t2=132.This gives 25+t2=169.Subtract 25 from both sides: t2=144.Take the square root: t=144.Since 12×12=144, we get t=12.Answer:t=12Option A.
