The sides of a triangle are 5 cm, 12 cm, and 13 cm. What is its area?

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A 60 cm²
B 30 cm²
C 15 cm²
D 40 cm²

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Answer: B. 30 cm²

s = (5 + 12 + 13) / 2 = 15.
Area = sqrt(15 x 10 x 3 x 2) = sqrt(900) = 30 cm².
(Also, 5² + 12² = 13², so it is a right triangle: area = 1/2 x 5 x 12 = 30 cm².)

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The sides of a triangle are 5 cm, 12 cm, and 13 cm. What is its area?

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