If a triangle has sides 4.8km, 28.6km and 29km, is the triangle a right triangle? Why or why not?

It is a right triangle.  

First, we sum the squares of 2 legs:

4.8^2 + 28.6^2 = 23.04 + 817.96 = 841

which equals the square of the longest side

29^2 = 841

When the sum of the squares of the 2 short sides of a triangle equals the square of the longest side, the triangle is a right triangle.

Step-by-step explanation: