In the triangle, AB = 4, AC = 5 and BC = 7. Calculate angle A to the nearest degree/ In the triangle, AB = 4, AC = 5 and BC = 7. Calculate angle A to the nearest degree/
Hint You can either use the cosine formula and find the $\cos$ of $A$;or use the Heron formula of the area and find the $\sin$.
Note that $\angle BAC=cos^{-1}(\frac{AC^2+AB^2-BC^2}{2 \cdot AC \cdot AB})$. You can use a calculator to get $\boxed{102}$ as the answer. It's about $101.537$
Hope this helped!