DIRECTIONS for the question: Solve the following question and mark the best possible option.
In the figure below, AD is a tangent and CD is a secant such that CD ´ BD = 225 cm. If radius of the circle is 8 cm, then what is the length of OD where O is the centre of the circle?
A)
15 cm
B)
16 cm
C)
17 cm
D)
21 cm
E)
24 cm
C
Using property, AD2 = CD.BD
AD = 15
OA = radius = 8
Radius on tangent is perpendicular, therefore AOD is right angled at A,
Therefore, AO2 + AD2 = OD2
AO = 17
