Q1 of 12 Page 115

In the figure, m∠B = 85° and m∠C = 105°, then find the measures of ∠A and ∠D.

As we know that


Sum of Opposite angles of cyclic quadrilateral are supplementary


If the opposite angles are ∠A&∠C ; ∠B&∠D


⇒ ∠A + ∠C = 180°


∠A = 180°-105° = 75°


⇒ ∠B + ∠D = 180°


∠ B = 180°-85° = 95°


∴ ∠A and ∠B are 75° and 95°


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