The base of an isosceles triangle is 7 cm longer than the legs. find the legs if the perimeter of the triangle is 43 cm.

An isosceles triangle is a triangle that has one pair of equal sides. The Formula in finding the perimeter of a triangle is PΔ=S₁+S₂+S₃. Since two legs are missing, and the given are the base and perimeter, we will use the formula : S₁+S₂ = PΔ-S₃, where: S₁+S₂ are the legs and S₃ is the base.
Substitute values:
S₁+S₂ = 43cm - 7 cm
          = 36 cm
since S₁ and S₂ are equal, divide 36cm by 2. Therefore S₁ and S₂ measures 18cm.
Check: PΔ=S₁+S₂+S₃
                 = 18cm + 18 cm + 7cm
                 = 43cm

The answer is option c.