Perimeter of an Isosceles triangle = 7.5 m
Shortest side = 2.1 m
Now,
We know, the other two sides in an isosceles triangle are equal to each other.
So,
the other two sides are going to be equal to "x"
Now,
Perimeter = Sum of all sides
7.5 m = 2.1m + x + x
2x = 7.5 m - 2.1 m <--- you are going to have to use this equation to find the values of x
x = 5.4 m / 2
x = 2.7 m
So, the other two sides are equal to 2.7m