Let side B = X
Then side A = 2x
Side C = 2x +1
Mow you have x + 2x + 2x+1 = 76
Simplify:
5x +1 = 76
Subtract 1 from both sides:
5x = 75
divide both sides by 5:
x = 75 /5
x = 15
Side A = 2x = 2*15 = 30 cm
Side B = x = 15 cm
Side C = 2x +1 = 2*15 +1 = 30+1 = 31 cm