Answer:
Coordinates of point R → (c - a, b)
Explanation:
From the picture attached,
By the property of an isosceles trapezoid,
PX = AY = a
Therefore, horizontal distance of Y from the origin PY = AP - AY
PY = c - a
Vertical distance of point R from x-axis (RY) = b
Therefore, coordinates of point R will be (c - a, b).