1.55: Sine Rule and Triangle Area

4PM1/1/June/2019 — Question 3 · 6 marks

In triangle ABC\displaystyle ABC, AC=7 cm\displaystyle AC=7\,\mathrm{cm}, BC=10 cm\displaystyle BC=10\,\mathrm{cm} and ∠BAC=65∘\displaystyle \angle BAC=65^\circ.
(a) Find, in degrees to the nearest 0.1∘\displaystyle 0.1^\circ, the size of ∠ABC\displaystyle \angle ABC.
(3)
(b) Find, in cm2\displaystyle \mathrm{cm}^2 to 3 significant figures, the area of triangle ABC\displaystyle ABC.
(3)