The angle subtended by a chord at the center is 90°. Its length is 8 cm. What is the radius?
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Correct answer: A
Explanation
Given:
Chord length = 8 cm
Angle at the center = 90°
Formula:
Chord = 2R sin(θ/2)
8 = 2R sin(90°/2)
8 = 2R sin45°
8 = 2R × (1/√2)
8 = √2 R
R = 8 / √2
R = 4√2 cm