How do I find the length of a line segment that does not have given points?

Answer:
Step-by-step explanation:
they give you points that are variable instead of numbers
P1=(a,0)
P2=(0,b)
also a and b are the length of that side of the triangle
so
MP = [tex]\sqrt{a^{2}+b^{2} }[/tex]
then what ever a and b are.. you're set
to show your work you could use the distance formula which will give you the same thing above
MP = [tex]\sqrt{(x2-x1)^{2}+(y2-y1)^{2} }[/tex]
MP = [tex]\sqrt{(-a)^{2}+b^{2} }[/tex]
which is just the formula above :)