BC = 15 cm and AC = 13 cm,Calculation:We know, AD = AF, DB = BE, CE = FCThe perimeter of the TRIANGLE = AB + BC + AC = 18 + 15 + 13 = 46That is, AD + AF + BD + BE + CE + CF = 46Or, 2 × (AD + BE + CF) = 46∴ AD + BE + CF = 23