(1) Given radius of bigger circle is 9cm.
Length of segment MT = 9cm.
(2) MT = MN+NT [M-N-T]
9 = MN+2.5 [Given radius of smaller circle is 2.5]
MN = 9-2.5
MN = 6.5cm.
(3) RM touches smaller circle at S.
MR is the tangent to the smaller circle. NS is the radius of smaller circle.
NSM = 90˚ [Tangent theorem]
In NSM , NS2+MS2 = MN2
2.52+MS2 = 6.52
MS2 = 6.52-2.52
MS2 = 42.25-6.25
MS2 = 36
MS = 6
MR = SR+SM [R-S-M]
9 = SR+6
SR = 9-6 = 3
MS:SR = 6:3 = 2:1