Question

If two circles with radii $8$cm and $3$cm respectively touch internally, then find the distance between their centres.

Answer 1

Fact: If two circles of radius $r_1$ and $r_2$ touch each other internally then,

Distance between their center will be $=|r_2-r_1|$

Here $r_1=3,r_2=8$ cm

Hence distance between their center is $=8-3=5$ cm