Physics relativity length contraction question

Hi, I have a physics question that Im doing wrong, but not sure how. It goes...

A vechicle travelling at .9c (0.9 times the speed of light) sees a brick wall. If this wall happens to be 80 meters as observed by the driver of the vechicle, how long is the actual wall according to an observer right beside it?

We are supposed to answer with the formula L=Lnot *The square root of 1-vsquared/csquared.

(If the answer is 253, I did it right!!)

Thx!!

L=Lnaught*SQRT(1-(v/c)²)
Lnaught=L/SQRT(1-(v/c)²)
=80/SQRT(1-(0.9c/c)²)
=80/SQRT(1-0.9²)
=80/SQRT(0.19)
=183.53m

Not completely sure what you did wrong, since you didn't show your steps, but that should be the right answer ^^

Cheers.

L = Lnot * sqrt(1-(v/c)^2)
Lnot = L / sqrt(1-(v/c)^2)
Lnot = (80 m) / sqrt(1-(0.9)^2) = (80m) / sqrt(0.19)
Lnot = 183.53 meters