This is an important and exam oriented question from Chapter name- circles
Topic – Angle properties of circles
Chapter number- 15
In this question we have figure of circles with constructions and we have to find the value of x using basic properties of circles.
ICSE Avichal publication
Understanding ICSE Mathematics
Question 2
∠ACB + ∠CBD = 180o
∠ABC + 75o = 180o
∠ABC = 180o – 75o‑ = 105o
Now arc AC Subtends reflex ∠AOC at the centre and ∠ ABC at the remaining part of the circle.
Reflex
∠AOC = 2 ∠ABC
= 2× 105o =210o
I hope this helps!!!!