Triangle $ABC$ has $AB = 7$ cm, $AC = 8$ cm and $BC = 13$ cm. Find $\angle A$ to \(1\

Question

Triangle $ABC$ has $AB = 7$ cm, $AC = 8$ cm and $BC = 13$ cm. Find $\angle A$ to $1$ decimal place [2] the area of triangle $ABC$ to $3$ s.f. [2]

Accepted Answer

(a) $120.0^\circ$ (b) $24.2\text{ cm}^2$.

Trigonometry