Question

Find the surface area of the come in terms of pi.

Answer 1

`144\pi` sq. cm.

Explanation:

Surface Area of cone is given by the formula
`\pi r^2+\pi rl`

The diameter is given as 12, hence radius (r) is half of that, 6.

The slant height (l) is given as 18

Plugging all the values into the formula, we get:

`\pi r^2 + \pi r l\\=\pi(6)^2+\pi (6)(18)\\=36\pi +108 \pi\\=144\pi`

First answer choice is right,
`144\pi` sq. cm.

Answer 2

Answer: first option

Explanation:

The formula for calculate the surface area of a cone is the shown below:

`SA=rs\pi+r^(2)\pi`

Where: s is the slant height and r is the radius.

As you can see in the figure the slant height and the radius are:

s=18 cm and r=6 cm

Therefore when you substitute the values shown above into the formula, you obtain that the result is:

`SA=(6cm)(18cm)\pi+(6cm)^(2)\pi=144\pi`cm²