Question

Choose which method to use: Law of Sines or Use Law of Cosines.

Answer 1

we have

b=3mm

c=5mm

a=?

angle =62°

By using cosine rule.

a²=b²+c²-2bc cos angle

a²=3²+5²-2×3×5 cos 62°

a²=19.92

a=√19.92

a=4.5

I had choose cosine rule.