Posted by Christy on .
Story problems are my favorite. However, I can not figure this one out. THe stopping distance d of a car after the breaks are applied varies directly as the square of the speed r. If a car traveling at 70mph can stop in 270 ft. How many feet will it take the same car to stop when traveling at 90mph

Algebra 2 
bobpursley,
distance=k*r^2
is the basic relationship. Take the 70/270f data, and solve for k.
then,
distance=k(90)^2