If a chord of length 24 cm is at a distance of 5 cm from center, then find the radius of the circle.

Correct option is A

Given:
AB = 24 cm
OC = 5 cm
Radius r = ? 

Theorem Used:  

$$(OB)^2 = (OC)^2+ (BC)^2$$ 

Solution:

BC = 24/2 = 12
As per Pythagoras theorem
​$$(OB)^2 = (OC)^2+ (BC)^2$$​​
​$$r^2 =122 + 52 \\\ \\r^2 = 144+25 \\\ \\r^2 = 169 \\\ \\r = 13 cm$$​​