Remember that
The total surface area of the box is equal to
SA=2B+Ph
where
B is the area of the rectangular base
P is the perimeter of the rectangular base
h is the height of the box
we have
B=(28)*(14)=392 cm2
P=2(28+14)=84 cm
h=10 cm
substitute the given values in the expression above
SA=2(392)+84(10)
SA=1,624 cm2
