total surface area of cuboid -
2(lb+bh+bl)
2(7×4+3×4+21)=2(28+12+21)
=2(40+21)
=2(61)=122
Archit = 120100 Deepak
-Deepak + Archit Archit×100=1.2Deepak-Deepak1.2Deepak
=0.21.2=×100=16.3%
Refer above image
AC2=AB2+BC2
AQ2=AB2+BC2+CD2
AD2=AC2+CD2
ACD=900