Question 467477
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?
The car will skid _____ feet.

{{{60=2sqrt(5L)}}} divide both sides by 2
{{{30=sqrt(5L)}}} square both sides
{{{900=5L}}} divide both sides by 5
{{{180=L}}}

To check:
{{{2sqrt(5*180)}}}
{{{2sqrt(900)}}}
{{{2*30}}}
60