Step-by-step explanation:
a. area of shaded region= area of rectangle -area of triangle
area= (17*14)-(1/2*8.7*9.5.sin72)
= 159.4m²
b.20l cover 20m²
so 159.4l would cover 159.4m²
20m²-->(cost)$ 21.99
159.4-->?
(21.99*169.4)÷20
=$175.3
