Respuesta :

bobeld
One way:

3x + 4x + 5 x = 30
12 x = 30
Divide by 12
x = 2.5

3x = 7.5   (2.5x3)
4x = 10     (2.5x4)
5x = 12.5   (2.5x5)

7.5cm + 10cm +12.5cm = 30cm  There are your three sides.   

Answer: 7.5 cm, 10 cm, 12.5 cm

Step-by-step explanation: