Answer:
see explanation
Step-by-step explanation:
The perimeter is the sum of the 3 sides of the triangle.
Sum the sides and equate to 54, that is
3x + 4x + 5x = 54, that is
12x = 54 ( divide both sides by 12 )
x = 4.5
Thus
AB = 3x = 3 × 4.5 = 13.5 in
BC = 4x = 4 × 4.5 = 18 in
AC = 5x = 5 × 4.5 = 22.5 in
