Question

if the sum of the length width and height of a cuboid is s mt and diagonal is d mt. Find its surface area

Answer 1

let a , b , and ,c are the sides of cuboid
a/c to question,
a+b+c=smt =============(1)

and √(a^2+b^2+c^2)=dmt ==========(2)

now from equation (1)
a+b+c=smt
squaring both side
a^2+b^2+c^2+2(ab+bc+ca)=(smt)^2
2(ab+bc+ca)=s^2m^2.t^2-dmt

now ,
surface area of cuboid=2(ab+bc+ca)
=(smt)^2-dmt