Answer:
20cm, 28cm, 40cm
Step-by-step explanation:
Let the shortest side be 4x, the middle side be 7x and the longest side be 10x.
4x + 7x + 10x = 105
21x = 105
x = 105 ÷ 21
x = 5
Shortest side (4x) = 5 × 4
Shortest side (4x) = 20
Middle side (7x) = 7 × 4
Middle side (7x) = 28
Longest side (10x) = 10 × 4
Longest side (10x) = 40