The length of the tangent drawn to a circle of radius 4

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The length of the tangent drawn to a circle of radius 4 cm from a point 5 cm away from the centre of the circle is

1. 3 cm
2. 4√2 cm
3. 5√2 cm
4. 3√2 cm

Correct Option: A

According to question , we draw a figure of a circle with centre O ,

∠OBA = 90°
Given that , OA = 5, OB = 4
∴ AB = √OA² - OB²
AB = √25 - 16
AB = √9 = 3 cm