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
