Answer:
3.5 m
Step-by-step explanation:
The perimeter is the sum of the lengths of the three sides of the triangle, so is the sum of two legs and the base.
... 7.5 m = (2 m) + (2 m) + base
... 3.5 m = base . . . . . . subtract 4 m
base = 3.5m
Since the triangle is isosceles both legs are equal to 2m
base = 7.5 - 2 - 2 = 3.5m