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PBA and PDC are two secants. AD is the diameter of the circle with center at O. ∠A = 40°, ∠P = 20°. Find the measure of ∠DBC.(a) 30° (b) 45° (c) 50° (d) 40° |
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Answer» Answer : (a) 30º In ∆ ADP, ext. ∠ADC = Int. ∠s (∠A + ∠P) = 40° + 20° = 60°. ∠ABC = ∠ADC = 60° (Angles in the same segment) \(\because\) AD is the diameter, ∠ABD = 90° ∴ ∠DBC = ∠ABD – ∠ABC = 90° – 60° = 30° |
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