TBQ - Interpret the angles — task. Maths CBSE Live product, Class 9 (2026-27).

A quadrilateral \(ABCD\) is inscribed in a circle. If \(AB\) is a diameter, what can you say about \(∠ACD\) and \(∠ABD\)? Give a mathematical explanation.

Answer:

The given information is pictorically illustrated as follows:

\(∠ACD\) and \(∠ABD\) are .

Reason:

Angles in the same segment of a circle are equal.
The angle subtended by a diameter at any point on the circle is 90°.
Equal arcs of a circle subtend equal angles at the centre.
The angle subtended by an arc at the centre of the circle is double the angle subtended by the arc at any point on the circle outside the arc.

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2. TBQ - Interpret the angles

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