Question

In the given figure O is the center of the circle and $\angle$BAC = ${25}^{\circ }$ , then the value of $\angle$ADB is :

• A. 40°
• B. 55°
• C. 50°
• D. 65°

Answer 1

The correct option is D

65°

$\angle$CBA = ${90}^{\circ }$ (Angle subtended by a diameter)

$\angle$ACB + $\angle$CBA + $\angle$BAC = ${180}^{\circ }$

$\angle$ACB + ${90}^{\circ }$ + ${25}^{\circ }$ = ${180}^{\circ }$

$\angle$ACB = ${65}^{\circ }$

But $\angle$ADB = $\angle$ACB (Angle subtended by the same chord)

Therefore $\angle$ADB = ${65}^{\circ }$