AB is a diameter of a circle and AC is its chord such that `angleBAC=30^(@)`. If the tangent at C intersects AB extended at D, then BC=BD.

Explanation

To solve the problem step by step, we will use the properties of circles, triangles, and angles.

### Step-by-Step Solution:

1. **Identify the Given Information:**
- AB is the diameter of the circle.
- AC is a chord such that ∠BAC = 30°.
- D is the point where the tangent at C intersects the extended line of AB.
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