Answer:
Step-by-step explanation:
Remark
The easiest way is to find the area of the trianlge and subtract the area of the circle.
Area of the triangle
Area of the triangle = 1/2 b * h
b = 40 km
h = 27 km
The height is a little tricky. Since the angle at the base is greater than 90, you have to extend the base. Drop a line from the peak to the base making a right angle with the base. This has been done for you: the height is 27 km
Area of the triangle = 1/2 * 40 * 27
Area of the triangle = 540
Area of the circle
Area of the circle = pi r^2
r = d/2
r = 12/2
r = 6
Area of the circle = pi * 6*6
Area of the circle = 3.14 * 36
area of the circle = 113.04
Area of the shaded region
Area of the shaded region = area of triangle - area of the circle
Area of the triangle = 540
Area of the circle = 113.04
Area of the shaded region = 540 - 113.04
Area of the shaded region = 426.96
