In a circle with centre at O (0, 0) and radius 5 cm, AB

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In a circle with centre at O (0, 0) and radius 5 cm, AB is a chord of length 8 cm. If OM is perpendicular to AB, then the length of OM is:

1. 2.5 cm.
2. 3 cm.
3. 4 cm.
4. 1 cm.

Correct Option: B

On the basis of question we draw a figure of a circle with centre O ,

Given , AB = 8 cm
AM = MB = 4 cm
OA = 5 cm
From ∆ AOM ,
∴ OM = √OA² - AM²
OM = √5² - 4²
OM = √25 - 16
OM = √9 = 3 cm