A right-angled triangle has perpendicular legs measuring 9 cm and 12 cm. What is the length of its hypotenuse?
Answer and explanation
Correct answer: D. 15 cm
- Step 1: Apply the Pythagorean theorem: c^2 = a^2 + b^2. Step 2. Substitute legs: c^2 = 9^2 + 12^2 = 81 + 144 = 225 => c = sqrt(225) = 15 cm. Answer: 15 cm. Why not the others: 14 cm is an approximation; 16 cm is 12 + 4; 21 cm simply adds the two legs (9 + 12).
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