The point (0.8, p) lies on the graph of y = sin⁻¹x…

Step 1. The value of $p$. $p = \sin^{-1}0.8 = 0.9273$.

Step 2. The value of $q$. $q = \cos^{-1}(-0.6) = \pi - \cos^{-1}0.6 = 2.2143$.

Step 3. The sum. A right triangle with sides $3, 4, 5$ has an angle with sine $0.8$ and cosine $0.6$. So $\cos^{-1}0.6 = \sin^{-1}0.8 = p$. Then $q = \pi - p$ and $p + q = \pi = 3.1416$.