Answers

2014-03-11T13:30:30+05:30
C is the mid-point on AB, so that AC = BC
Now the mid-point of the hypotenuse of a right triangle is equidistant from the vertices.
Therefore, AC = BC = OC
hence, AC = BC = 6.5cm [since, OC = 6.5cm]
Now, AB = AC + BC = 6.5 + 6.5 = 13cm
According to Pythagoras rule,
 OB² = AB² - AO²
 OB² = 13² - 12²
 OB² = 169 - 144 = 25
 OB = √25 = 5cm 
2 3 2