ABCD is a cyclic quadrilateral and AD is a diameter. If

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ABCD is a cyclic quadrilateral and AD is a diameter. If ∠DAC = 55° then value of ∠ABC is

1. 55°
2. 35°
3. 145°
4. 125°

Correct Option: C

According to question , we draw a figure of cyclic quadrilateral ABCD and AD is a diameter ,

In ∆ ACD
Given , ∠DAC = 55°
∠ACD = 90°
∠D = 180° – 55° – 90° = 35°
∴ ∠ABC + ∠ADC = 180°
⇒ ∠ABC = 180° – 35° = 145°