Question

In the given figure, O is the centre of the circle
and AB is a tangent. If OB = 5 cm and AB = 12 cm,
then the length of AC
​

Answer 1

Step-by-step explanation:

Given ,

AB = 15 cm , AC = 7.5 cm

Let's assume the radius of the circle to be 'r'

So AO = AC + OC = 7.5 + r

In right ΔAOB , we have

AO

2

=AB

2

+OB

2

(7.5+r)

2

=15

2

+r

2

56.25+r

2

+15r=225+r

2

15r=225−56.25

r=168.75/15

Thus,

r=11.25 cm