Answer: Rectangle
Explanation: A rectangle has two long sides and two short sides.
Each of the short sides would be 50 steps and each of the long sides would be 100 steps. If it was a square, all the steps would be the same number.
if it was a triangle, all the steps would be equal (depending on the type of triangle).
Its definitely not a circle because it would say Mila took 100 steps to form a full circle