In the given diagram, a circle is inscribed in a right angled triangle such that AF = 6 cm and EC = 15 cm. Find the difference between CD and BD.
1 cm
As the lengths of tangents drawn from an external point to a circle are equal
AF = AE = 6
CE = CD = 15
Let BF = BD = x
Applying Pythagoras theorem to the above figure
(6+x)2+(6+15)2=(15+x)2
36+x2+12x+441=225+x2+30x
18x=252
x=14
Difference between CD and BD = 15 – 14 = 1 cm