Asquare wall tile has an area of 58,800 square millimeters. between which two measurements is the length of one side

As you know, all the four sides of a square has equal length 
To find the area of square you need this : A = a² (A- area and a is the lenght of sides).
As we do not know the length but we already have the area from the task, here is solution for one side of the square :
We just need to get the square root of the area:
A = a²
4220 = a²
√4220 = √a²
a = 64.9615271

Do hope you still need the answer because this one is 100% correct.

so the perpendicular line goes through the given pointyou would get a perpendicular line at some random location

step-by-step explanation:

points a and b are equidistant from the desired line, so the line you find by using them will go through point r.

using points other than a and b will give the desired line only if they are equidistant from r. if they are randomly located, the perpendicular line you create will not necessarily go through point r, hence will not be a solution to the problem.