An extension of the Pythagorean Theorem results in what is the so-called "distance formula".
d^2=(x2-x1)^2+(y2-y1)^2, in this case you have points (-2,4) and (2,0) so:
d^2=(2--2)^2+(0-4)^2
d^2=4^2+(-4)^2
d^2=16+16
d^2=2*16
d=√32 units
d=√(2*16)
d=4√2 units
d≈5.66 units (to nearest hundredth of a unit)
