Question

Radii of two circles are 6.3 cm and 3.6 cm. State the distance between their centres if:

1. they touch each other externally,
2. they touch each other internally.

Answer 1

Radius of bigger circle = 6.3 cm

And radius of smaller circle = 3.6 cm

i.

Two circles are touching each other at P externally. O and O' are the centers of the circles. Join

OP and O'P

OP = 6.3 cm, O'P = 3.6 cm

Adding,

OP + O'P = 6.3 + 3.6 = 9.9 cm

ii. 

Two circles are touching each other at P internally. O and O' are the centers of the circles. Join

OP and O'P

OP = 6.3 cm, O’P = 3.6 cm

OO’ = OP – O’P = 6.3 – 3.6 = 2.7 cm