One of the most important and exam oriented question from Chapter name- circles
Topic – Angle properties of circles
Chapter number- 15
In this question we have O is the centre of the circle.
Also Tangents to the circle at A and B meet at C. If ∠ACO = 30°,
Now we have to find (i) ∠BCO (ii) ∠AOR (iii) ∠APB
ICSE Avichal publication
Understanding ICSE Mathematics
Question 23
Solution:
(i) ∠BCO = ∠ACO = 30°
(∵ C is the intersecting point of tangent AC and BC)
(ii) ∠OAC = ∠OBC = 90°
∵∠AOC = ∠BOC = 180° – (90° + 30°) = 60°
(∵ sum of the three angles a ∆ is 180°)