Question 467838
The formula r=2sqrt(5l) can be used to approximate the speed r, in miles per
 hour, of a car that has left skid marks of length l, in feet.
 How far will a car skid at 60 mph?
:
Write it:
{{{2sqrt(5L)}}} = 60
divide both sides by 2
{{{sqrt(5L)}}} = 30
square both sides
5L = 30^2
5L = 900
L = {{{900/5}}}
L = 180 ft skid marks
:
:
Check on a calc: enter 2*{{{sqrt(5*180)}}}