The cross-sectional area of the parabolic tunnel is 31415.93 ft²
A parabolic tunnel assumes the shape of a hemisphere and the cross-sectional area of a hemisphere can be calculated by using the formula:
Area of a parabolic tunnel = πa²
Since the parabolic tunnel assumes the shape of a hemisphere:
Area of a parabolic tunnel = πa²
Area of a parabolic tunnel = π(100)²
Area of a parabolic tunnel = 31415.93 ft²
Learn more about the cross-sectional area of the parabolic tunnel here:
https://brainly.com/question/17143004