Answer:
Area of the shaded area = 60 m^2
Step-by-step explanation:
Remark
I don't think you need the 40 degrees for anything.
Formula
Area of Shaded part = area of the rectangle - area of the triangle
Solution
Area of the Rectangle
L = 12 meters
W = 10 meters
Area = 12 * 10
Area = 120 m^2
Area of the triangle
Area = 1/2 b * h
b = 12
h = 10
Area = 1/2 * 12 * 10
Area = 120/2 = 60
Area of the shaded area
120 - 60 = 60
