Answer:
6cm, 12cm, 18cm
Step-by-step explanation:
Let the shortest side be "a" and the common difference will be "d"
Hence, the four sides form an arithmetic sequence: a, a + d, a + 2d, a + 3d because of a + (n-1)d
The sum of the four sides is the perimeter
a + (a + d) + (a + 2d) + (a + 3d) = 4a + 6d
4a + 6d = 60
2a + 3d = 30 (Equation 1)
The longest side, a + 3d, has a length of 24cm
a + 3d = 24 (Equation 2)
Solve simultaneously
2a + 3d = 30
- a + 3d = 24
a = 6
6 + 3d = 24
3d = 18
d = 6
The other side lengths are a, a+d, a+2d
= 6cm, 12cm, 18cm