Answer:
150 m
Explanation:
Since we have a dome inscribed in a rectangle, and are given the width of the rectangle, we can,
1. Find the diameter of the circle, which is also 150m
2. Find the length of the rectangle, which is 75m (the length of the rectangle is the same as the radius of the circle)
If we are to find the perimeter of the shaded region, we add the length and half the width of the rectangle. So,
75 + 75 = 150m