The Total solution for NCERT class 6-12
Let the radius of a circle be r.Circumference of a circle = 2╧АrLet the radii of two circles are r1 andr2 whosevalues are 15 cm and 18 cm respectively.i.e., r1 = 15 cmand r2 = 18 cmNow, by given condition,Circumference of circle = Circumference of first circle + Circumference of secondcircleтЗТ 2╧Аr = 2╧А r1 + 2╧Аr2 =тЗТ r = r1 + r2тЗТ r = 15 + 18тИ┤ r = 33cmHence, required radius of a circle is 33 cm.