The formula for the surface area is 2(lw + lh + wh). So all you have to do is plug the values in. Box A:2(lw + lh + wh)2( (4x6) + (4x25) + (6x25) ). 2(24+100+150)2(274)548=Surface Area
Box B:2(lw + lh + wh)2( (9x5) + (9x11) + (5x11) ). 2(45+99+55)2(199)398=Surface Area
Box C:2(lw + lh + wh)2( (10x5) + (10x8) + (5x8) ). 2(50+80+40)2(170)340=Surface Area
