These are the steps:
1. Find the area of the trapezium {Whole figure).
2. FInd the area of the rectangle (unshaded).
3. Area of the shaded = Area of trapezium - Area of the rectangle.
Step 1: Find the area of the trapezium:
Formula : Area of trapezium = 1/2 (a + b)h
Area = 1/2 ( 25 + 15) (12) = 240 yd²
Step 2 : Find the area of the rectangle:
Formula : Area = Length x Width
Area = 12 x 3 = 36 yd²
Step 3: Find the shaded region:
240 - 36 = 204 yd²
Answer: 204 yd²