Answer:
Solving the triangle means you are to find A , B and C
and this can be done using cosine rule:
Cos A = b^2 +c^2 - a^2 / 2bc
Cos B = a^2 + c^2 - b^2 / 2ac
Cos C = a^2 + b^2 - c^2 / 2ab
substituting 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
= 274/338
therefore A = Cos^-1 274/338
A = 35.8404
follow the same step to calculate B
Cos B = 64 + 169 - 169/ 2 x 8x 13
Cos B = 64/ 208
B = Cos^-1 64/ 208
B = 72. 0797
Since the triangle is isosceles, it implies B = C
Therefore A ≈ 35.8404 , B ≈ 72. 0797 and C ≈ 72.0797
Explanation: