Question

A cylinder has a circular base with a diameter of 14 cm and a height of 20 cm. What is its curved surface area and total surface area?

• A. Total Surface Area $=280\pi c{m}^2$
  Curved Surface Area $=329\pi c{m}^2$
• B. Total Surface Area $=378\pi c{m}^2$
  Curved Surface Area $=329\pi c{m}^2$
• C. Total Surface Area $=378\pi c{m}^2$
  Curved Surface Area $=280\pi c{m}^2$
• D. Total Surface Area $=378\pi c{m}^2$
  Curved Surface Area $=210\pi c{m}^2$

Answer 1

The correct option is C Total Surface Area $=378\pi c{m}^2$

Curved Surface Area $=280\pi c{m}^2$
Here we know the diameter of the circle as 14 cm. So, the radius would be half of the diameter.
$radius=r=\frac{1}{2}\times 14$
$r=7cm$


Curved Surface Area $=2\pi rh$

Curved Surface Area $=2\pi \left(7\right)\left(20\right)$

Curved Surface Area $=280\pi c{m}^2$

Total Surface Area = Curved Surface Area + $2\pi r^2$
Total Surface Area $=280\pi +2\pi (7{)}^2$
Total Surface Area $=280\pi +98\pi$
Total Surface Area $=378\pi c{m}^2$