In Fig.10.5, if AOB is the diameter of the circle and AC = BC, then is equal to:
(A) 30º
(B) 60º
(C) 90º
(D) 45º
We know that diameter subtends a right angle to the circle.
Now,
AC = BC
(Angles opposite to equal sides are equal in a triangle)
In
(By angle sum property of a triangle)
Therefore option (D) is correct.