First, notice the following right triangle that we can get with the vertices Q,S and P:
then, we can find PS and QS using the trigonometric functions sine and cosine:

therefore, PS = 3.99 and QS = 2.07
Now, notice that the base of the triangle PQR is:

since we already know that SR = 5, we have that the base of the triangle is:

Now we can find the area of the triangle PQR:

therefore, the area of triangle PQR is 14.11 u^2