Question

there is a room 7 feet x 9 feet you lay a 1-foot wide plank from corner to corner touching all 4 walls how long is the plank

Answer 1

Explanation:

l^2=[(7-V2)/2]^2+(9-V2/2)^2=

49-7V2+2/4+81-9V2+2/4=

49+81+4/4-16V2=

131-16V2=108.4 ft

so l=V108.4≈10.4ft