Question

look at the adjoining figure in which O is the Center of the circle if AB =8CM. OP =3CM find the radius of the circle

Answer 1

given that AB is 8 cm
and OP is 3 cm
from the figure
AP = BP = 4 cm as angle OPA is 90 degree

AOP is a right angled triangle
so AO ^ 2 = AP ^ 2 + OP ^ 2
=> AO ^ 2 = 4^2 + 3^2
=> AO ^ 2 = 16 + 9
=> AO ^ 2 = 25
= > AO = 5 cm

therefore radius of the circle is 5 cm