The length of a hall is 18m and the width 12m. The sum of the areas of the floor and the flat roof is equal to the sum of the areas of the four walls. Find the height of the hall.

Explanation

Length of hall`=18 m`
Width of hall`=12 m`
Let height of hall be `h` metre
Sum of area of floor and flat roof`=(lb+lb)=(12times18+12times18)=(216+216)=432 m^2`
Sum of area of `4` walls`=2(l\timesh+btimesh)=2(18timesh+12timesh)=2(18h+12h)=2(30h)=60h m^2`
Sum of area of 4 walls`=`Sum of area of floor and flat roof
`60h=432`
`h=432/60=7.2m`
`therefore` Height of hall`=7.2 m`