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Two tangents PA and PB are drawn from an external point P to a circle. If angle APB = 60 degrees, then angle AOB equals
A60 degrees
B90 degrees
C150 degrees
D120 degrees
Answer & Solution
Correct answer: D. 120 degrees
1. In quadrilateral OAPB, angles OAP and OBP are both 90 degrees (tangent perpendicular to radius).
2. Sum of all four angles = 360 degrees, so AOB + APB = 180.
3. AOB = 180 - 60 = 120 degrees.
_Source: NCERT Class 10 Mathematics, Ch 10 "Circles", §10.3_
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