AB is diameter of a circle and AC is it chord such that

1.	AB is diameter of a circle and AC is it chord such that
Answer» Let O be the centre of the circle. By Tangent Chord Theorem ∠CAB =∠BCD=30° …(1) Also ∠OCD=90° [∵Angle between Tangent and radius is 90° ] ∴∠BCO=90°-30°=60°. Also ∠CBO=60° because, Angle opposite to equal sides (radii) are equal. And hence ΔOBC must be a Equilateral Triangle. ∴∠COB=60°. Also in Right Triangle OCD, ∠CDO=90°-60°=30° …(2) From (1) and (2) BC=BD because Sides opposite to equal angles are equal in a triangle

Answer»

Let O be the centre of the circle.

By Tangent Chord Theorem ∠CAB =∠BCD=30° …(1)

Also ∠OCD=90° [∵Angle between Tangent and radius is 90° ]

∴∠BCO=90°-30°=60°. Also ∠CBO=60° because, Angle opposite to equal sides (radii) are equal.

And hence ΔOBC must be a Equilateral Triangle. ∴∠COB=60°.

Also in Right Triangle OCD, ∠CDO=90°-60°=30° …(2)

From (1) and (2) BC=BD because Sides opposite to equal angles are equal in a triangle

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