#### Answer

Area = =$\frac{1}{2}$*(5.3)*(8.4)*sin 57°

#### Work Step by Step

Given,
a=5.3, c=8.4, α = 36° , γ =87°
As we know sum of all the angles of the triangle is 180°
α + β +γ = 180°
36°+ β +87°=180°
β = 57°
By theorem 11.4.1
Area of triangle = $\frac{1}{2}$a*c*sinβ
=$\frac{1}{2}$*(5.3)*(8.4)*sin 57°