3 right circular cylinders having the same base radius (r cm) and the same height (h cm) are placed one upon the other, to form another right cylinder whose radius of base is also r cm. The total surface area (in $$\text{cm}^2$$) of this new right cylindrical solid so formed is:

Correct option is B

Given:

3 right circular cylinder having same base(r cm) and same height(h cm) are placed upon one another

Formula Used:

Total surface area of cylinder = $$2\pi rh + 2 \pi r^2$$​​

Solution:

When cylinders are joined height will be = 3h cm

Radius of base is same = r cm

Total surface area =$$2 \pi r(3h) + 2 \pi r^2$$​

= $$6 \pi rh + 2 \pi r^2$$​​