From a point Q, the length of the tangent to a circle is 24 cm and the distance of Q from the centre is 25 cm. The radius of the circle is
(A) 7 cm     (B) 12 cm     (C) 15 cm     (D) 24.5 cm

Explanation

To find the radius of the circle given the length of the tangent from point Q and the distance from Q to the center of the circle, we can use the Pythagorean theorem. Here’s the step-by-step solution:

### Step 1: Understand the Problem
We have a point Q outside the circle. The length of the tangent from point Q to the circle is given as 24 cm, and the distance from point Q to the center of the circle (let's call it O) is 25 cm. We need to find the radius of the circle (let's call it r).

### Step 2: Identify the Right Triangle
When a tangent is drawn from a point outside the circle to the point of tangency (let's call it P), the radius (OP) is perpendicular to the tangent (PQ). Therefore, we can form a right triangle OQP, where:
- OQ = distance from Q to O = 25 cm (hypotenuse)
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