The perimeter of the triangle is 123 cm, and the lengths of its sides are referred to as 10:12:19. Find the sides of the triangle.

1. If the sides are 10: 12: 19, let the length of one part be equal to y. Then we get:
10y + 12y + 19y = 123,
41y = 123,
y = 123/41,
y = 3 cm.
2. Find each side of the triangle by multiplying the number of parts of the sides by 3 cm:
1 side = 10 * 3 = 30 cm.
2 side = 12 * 3 = 36 cm.
3 side = 19 * 3 = 57 cm.
Answer: the sides of the triangle are 30 cm, 36 cm and 57 cm.