Let be a, b, c be the lengths of sides of a triangle; a=4.8, b=0.23, c is a whole number. find c.

It's not clear if this is a right triangle or not. I'm going to assume its any kind of triangle. The third side c is restricted such that...

a - b < c < a + b
4.8 - 0.23 < c < 4.8 + 0.23
4.57 < c < 5.03

If c was allowed to be any real number, then we'd have infinitely many solutions for c. However, we're told that c is a whole number. The only whole number between 4.57 and 5.03 is 5

So c = 5 is the only integer solution

Final 5