Question $2-$ Average Area End Method

Your company is installing $500$ linear feet of a $4^{\text{'}}$ high $6^{\text{'}}$ wide precast concrete box

culvert to carry stormwater. The bottom of the trench at the point of connection is at an

elevation of $1,{235}^{\text{'}}.$ The existing ground surface elevation slopes at $-75\%$ BELOW

horizontal $($falls$)$ along the length of the box culvert. The bottom of the trench is required to

extend a horizontal distance of $2\mathrm{.}5$ outside each face of the box culvert. The sides of the

trench will be sloped at to $1$ V