Question

Two circles having radii 4 cm and 5 cm touch each other internally. Then the distance between the centres is ______.

Options

• 4 cm

• 5 cm

• 1 cm

• 9 cm

Answer 1

Two circles having radii 4 cm and 5 cm touch each other internally. Then the distance between the centres is 1 cm.

Explanation:

For internally tangent circles, centers are collinear, and the distance between centers equals the difference of their radii.

Thus,

Distance = 5 cm − 4 cm

= 1 cm