Answer:
426.9 Km²
Step-by-step explanation:
The shaded area is the area of the triangle subtract the area of the circle.
Area of triangle = 0.5 bh ( b is the base and h the perpendicular height )
Here b = 40 and h = 27, thus
Area = 0.5 × 40 × 27 = 20 × 27 = 540 Km²
Area of circle = πr² ← r is the radius
Here the diameter is 12, thus radius = 12 ÷ 2 = 6
Area = π × 6² = 36π ≈ 113.1 Km²
Shaded area = 540 - 113.1 = 426.9 Km²