The bed of a pick up truck measures 4' x 8" to the nearest inch what is the length of the longest thin metal bar that will lie flat in the bed

Ok so what y ou want to do it to max space, lie it diagonally
use pythagoren theorem
first convert the units

4'=4 feet
8''=8 inches
convert to inches
4 feet times 12=48 inches

so
pythagorea theorem is
a^2+b^2=c^2
c=hypotonuse
a and b are legs
in a right triangle

8 and 48 are the legs
fidn hypotonuse

8^2+48^2=c^2
64+2304=c^2
2368=c^2
8√37=c
aprox
48.66=c
4 feet amd 0.66 inches

You can find it by multiplying the areas it show u