Question

Three identical cubes of side 5cm are joined end to end. Find the total surface area and lateral surface area f the resulting cuboid so formed.

• A. TSA= 300 cm${}^2$ CSA= 100 cm${}^2$
• B. TSA = 360 cm${}^2$ CSA = 190 cm${}^2$
• C. TSA = 350 cm${}^2$ CSA = 200 cm${}^2$
• D. TSA = 366 cm${}^2$ CSA = 133 cm${}^2$

Answer 1

The correct option is C TSA = 350 cm${}^2$ CSA = 200 cm${}^2$


Length of the resulting cuboid = 5 + 5 + 5 = 15cm
Breadth of a cuboid = 5cm
Height of a cuboid = 5cm
Curved surface area of resulting cuboid = 2h (l+b)
= 2(5) (15 + 5)
= 10 (20)
= 200 cm${}^2$
Total surface area 2(lb + bh + hl) = 2[15(5) + 5(5) + 5(15)]
=2[75 + 25 + 75]
= 2(175)
= 350 cm${}^2$
Hence, the correct answer is option (c)