The altitude of an equilateral triangle is 15 cm. Find its area and perimeter.
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Correct answer: B
Explanation
Height of the equilateral triangle = 15 cm
Height = (√3 / 2) × Side
15 = (√3 / 2) × Side
Side = (2 × 15) / √3 = 10√3
Area = (√3 / 4) × Side²
Area = (√3 / 4) × (10√3)² = 75√3
Perimeter = 3 × Side
Perimeter = 3 × 10√3 = 30√3
Area = 75√3 cm², Perimeter = 30√3 cm