
Mathematically, the sum of angles in a triangle is 180
The angles in an equilateral triangle are equal and that means each of the angle measure is 60 degrees each
Since the measure of angle P is in the equilateral triangle, we have it that the measure of angle P is 60 degrees
Now, we can see that q and p lie on a straight line
Mathematically, the sum of angles in a straight line is 180
This mean that the two angles sum up to be 180
Thus;

For a parallelofgram, angles that are directly opposite on the diagonal stretch are equal
This means that r is equal to q which is 120
Lastly, angles that are on same base are supplementary
That means s added to q will give 180
So, we have it that;
