Question

Is it possible to make a triangle with 4 meters, 5 meters, and 7 meters

Answer 1

The triangle Inequality Theorem states that if the longest side is shorter than the sum of the other 2 sides, it will form a triangle.
7< 4 + 5 so it forms a triangle.

It is a scalene triangle (all 3 sides are not equal).

It makes an obtuse triangle.  (To see why, click here:  http://www.1728.org/triantest.htm )