Answer: 1) Mathematical object - Circle
2) Radius of path 1 is 1.5 km.
Explanation:
Since we have given that
He wants Path 1 to be a continuous distance of 1.5 km from the center of the habitat.
1) Path 1 represents circle as the distance with radius is possible with mathematical object -"Circle " only.
As we know that radius is the distance from the center of the circle to any surface of the circle .
As he is covered 1.5 km from the center of the habitat.
2) the radius of the path 1 is 1.5 km.