Answer:Solving the triangle means you are to find A , B and Cand this can be done using cosine rule:Cos A = b^2 +c^2 - a^2 / 2bcCos B = a^2 + c^2 - b^2 / 2acCos C = a^2 + b^2 - c^2 / 2absubstituting the values of a , b and c into the formulas above we have Cos A = 13^2 + 13^2 - 8 ^2 / 2 x 13 x 13 = 169 + 169 - 64 / 2 x 169 = 338 - 64 / 338 = 274/338therefore A = Cos^-1 274/338 A = 35.8404follow the same step to calculate BCos B = 64 + 169 - 169/ 2 x 8x 13Cos B = 64/ 208 B = Cos^-1 64/ 208 B = 72. 0797Since the triangle is isosceles, it implies B = CTherefore A ≈ 35.8404 , B ≈ 72. 0797 and C ≈ 72.0797Step-by-step explanation: