Answer:
A = 10 units^2
Step-by-step explanation:
If you'll draw this rectangle you'll see immediately that the base is (9 - 4), or 5 units and the height is 4 units (5 - 1).
Thus, the area of this triangle is A = (1/2)(base)(height) = (1/2)(5 units)(4 units), or
A = 10 units^2
