Page 8 - Lesson note-7 Extra Questions Ch.10 Circle
P. 8
But ∠A + ∠B + ∠C = 180°
⇒ ∠B + ∠C = 180° – ∠A
⇒∠B/2 + ∠C /2 = 90° – ∠A /2
∴ (iv) becomes, ∠D = 90° – ∠A /2 .
Similarly, from (ii) and (iii), we can prove that ∠E = 90° – ∠B/2
and ∠F = 90° – ∠C/2
