Answer:
The sides are 6, 6 and 9
Explanation:
Isosoles triangles have two sides the same length, s
Here the third side is 3 meters longer (s + 3)
therefor the perimeter is
s + s + (s + 3) = 21
Combine like terms
3s + 3 = 21
Subtract 3 from both sides
3s = 18
Divide both sides by 3
s = 6
s + 3 = 9
The sides are 6, 6 and 9