You have 2 alternative geometric representations.
Cord AP could be above the diameter AB along with AQ,
or AP could be above AB and AQ could be below.
Suppose they are both above the diameter AB.
Draw the radius from the centre O to Q.
You may calculate any angle in the isosceles triangle AQO
using the Law of Cosines (Cosine Rule).
This allows you to calculate angle QOB.
Hence you can calculate the area of sector QOB.
You can also calculate the area of triangle AQO.
Now draw the radius from P to the circle centre O.
The area between the arc AP and the triangle APO can be found similarly.
Subtract the 3 areas from the area of the semicircle for the final answer.
That's one way.