Given is a circle with centre at C. A, B and D are the points on the circumference. Find ∠ABC.
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 30°.
Let us join points BD
Hence, the 2 sides of the ΔBCD i.e. BC and CD are equal
Hence, the ∠CBA and ∠CDB are equal
Let us denote these 2 angles by x
Now since the sum of the interior angles of the ΔBCD is 180
⇒ 126 + x + x = 180
⇒ x = 27
Now in ΔABD
∠A = ∠BCD
⇒ ∠A = 63
Now the sum of the interior angles of the ΔABC is 180
⇒ 63 + (27 + 33) + (∠ABC + 27) = 180
⇒ ∠ABC = 30°