Question

Three cubes each of 5cm are joined end to end. Find
the surface area of the resulting cuboid?

Answer 1

given
edge of each cube =5cm
if 3 cubes are joined end to end the resulting figure is cuboid
measurements of cubiod are
l=15cm, b=5 cm, h=5cm
total surface area =2(lb+bh+lh)
=2(15×5+5×5+15×5)
=2(75+25+75)
=2×175
=350 sq cm

Answer 2

IF THE 3 CUBES OF 5 CM ARE JOINED THEY FORM A CUBOID 
THEN L =(5+5+5)CM = 15 CM
B = 5 CM 
H =5 CM 
THE SURFACE AREA OF CUBOID = 2 (LB +BH + HL)
= 2 ( 15 *5 +5 * 5 + 5* 15)
= 2 ( 75 + 25 + 75)
= 2 * 175
= 350 CM