In the figure, `O D` is perpendicular to the chord `A B` of a circle whose centre is `Odot` If `B C` is a diameter, show that `C A=2O Ddot`

Explanation

To solve the problem, we need to show that \( CA = 2 \cdot OD \) given that \( OD \) is perpendicular to the chord \( AB \) and \( BC \) is a diameter of the circle.

### Step-by-Step Solution:

1. **Understand the Given Information:**
- Let \( O \) be the center of the circle.
- \( OD \) is perpendicular to the chord \( AB \).
- \( BC \) is a diameter of the circle.
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