Find the perimeter of the triangle ABC if AB = 2.8 cm, and BC is more than AB by 0.8 cm, but less than AC by 1.1 cm.

The task:
AB = 2.8 cm,
BC =? cm, 0.8 cm more AB, but 1.1 cm less than AC,
AC =? cm,
perimeter P =? cm.
Solution:
1) define the BC:
BC = AB + 0.8 = 2.8 + 0.8 = 3.6 cm;
2) calculate the AC:
AC = BC + 1.1 = 3.6 + 1.1 = 4.7 cm;
3) find the perimeter of the triangle:
P = AB + BC + AC = 2.8 + 3.6 + 4.7 = 11.1 cm.
Answer: the perimeter of the triangle is P = 11.1 cm.