A circle is inscribed in a triangle ABC.  It touches the sides AB, BC and AC at the points R, P and Q respectively.  If AQ = 3.5 cm, PC = 6.5 cm and BR = 8 cm, then the perimeter of the triangle ABC is?

36 cm

With the help of Tangent property

AQ = AR = 3.5 cm

BR = BP = 8 cm

PC = CQ = 6.5 cm

Perimeter = AB + BC + CA

               = AR + RB + BP + PC + CQ + AQ

               = 3.5 + 8 + 8 + 6.5 + 6.5 + 3.5 = 36 cm