In a circle with center O, AB is the diameter and CD is a chord such that ABCD is a trapezium. If ∠BAC = 30°, then ∠CAD is equal to?
Answer & explanation
Correct answer: option 2
In ΔACB
∠ACB = 90° (angle in semicircle)
∠ABC = 90° - 30° = 60°
∠ADC = 120° (cyclic quad.)
∠DCA = ∠CAB = 30° (alternate angle)
∠CAD = 180° - (120° + 30°) = 30°