If I is the incentre of triangle ABC and AI when produced meets the circumcircle of triangle ABC in point D. If ∠BAC = 66° and ∠ABC = 80°. Calculate : ∠DBC
Exercise 17 (C) | Q 9.1 | Page 266
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Join DB and DC, IB and IC
∠BAC 66°, ∠ABC 80°, I is the incentre of the ΔABC,
since ∠DBC and ∠DACare in the same segment
∠DBC =∠DAC
$\text { But, } \angle D A C=\frac{1}{2} \angle B A C=\frac{1}{2} \times 66^{\circ}=33^{\circ}=$
$\therefore \angle DBC =33^{\circ}$
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