Question 351991
diagonal of floor: 
a^2+b^2=c^2
7^2+4^2
=49+16
=65
sqrt(65)=diagonal of floor.
.
length of the longest diagonal from one corner to another corner of the room:
sqrt(65)^2+2.5^2
=65+6.25
=71.25
sqrt(71.25)=8.44 m
.
Ed