2025 · Q84
An arc AB of a circle subtends an angle x radians at the centre O of the circle. If the area of sector AOB is equal to half the square of the length of arc AB, then what is x equal to?
Elementary MathematicsCircles
- A1/4
- B1/2
- C1
- D2
Explanation
Arc length = rx and sector area = r²x/2; setting r²x/2 = (rx)²/2 gives x = x², so x = 1 (x > 0), option (c).