Answer:
3.5 square units
Step-by-step explanation:
We can model the situation as:
Now, the area of the triangle is equal to the area of the square less the areas A, B, and C.
So, the area of the square is equal to:
Area Square = Side x Side = 3 x 3 = 9
On the other hand, the area of the triangles A, B, and C are:
Therefore, the area of the triangle with vertices P, Q, and R is:
Area = Area Square - ( Area A + Area B + Area C)
Area = 9 - ( 3 + 1 + 1.5)
Area = 9 - 5.5
Area = 3.5
So, the answer is 3.5 square units