Question

Find the length of the hypotenuse of a right triangle if a = 9 and b = 12.

A) 10.5
B) 15
C) 16.5
D) 21

Answer 1

Answer: B. 15.

Explanation: A right triangle is a triangle that contains one right angle. The sides that make up the right angle are the legs, and the sides opposite the right angle is the hypotenuse. The hypotenuse is always the longest side of a right triangle. Use the Pythagorean theorem to find the length of the hypotenuse, c.

Pythagorean theorem: a²+b²=c²

2²+12²=c²

2²=2*2=4

12²=12*12=144

4+144=c²

c²=225

C=15 ←← *Final Answer (correct)!*

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Answer 2

Let c be the hypotenuse
so by pythagoras theorem
a^2+b^2=c^2
2^2+12^2=c^2
4+144=c^2
C^2=225
C=15