Question

The diameter of base of a right circular cone is 7 cm and slant height is 10 cm, then what is its lateral surface area? Select one:

Answer 1

Answer:

Step-by-step explanation:

Radius = r = 7/2 cm

slant height = l = 10 cm

Lateral surface area of cone = πrl

= 22/7 * (7/2) * 10

= 11*10 = 110 sq. Cm

Answer 2

Given,

Base diameter of a cone = 7 cm,

Slant height = 10 cm.

To find,

The lateral surface area of the cone.

Solution,

The lateral surface area of an object is defined as the area of all the sides of the object without including the base and the top of the object.

For a cone, the lateral surface area is given by,

$LSA=\pi rl$

Where,

r = the radius of the base, and,

l = slant height.

For the given cone, base diameter = 7 cm

⇒ $r=\frac{d}{2}$

⇒ $r = \frac{7}{2} cm$

Slant height, l = 10 cm,

So,

$LSA=\pi \times \frac{7}{2} \times 10$

Taking $\pi =\frac{22}{7}$, and simplifying,

$LSA=\frac{22}{7} \times \frac{7}{2} \times 10$

⇒ $LSA=110 \hspace{3} cm^2$

Therefore, the lateral surface area of the cone will be 110 cm².