Question

Find area of a cone
Show work

Answer 1

Answer: 138.16 in²

Explanation:

You need to use this formula to calculate the surface area of the cone:

`SA = \pi r^2 + \pi rl`

Where "r" is the radius, "h" is the height and "l" is the slant height.

To find the height you need to use the Pythagorean Theorem:

`a^2=b^2+c^2`

Where "a" is the hypotenuse and "b" and "c" are the legs of the triangle.

In this case:

`a=l=7in\\\\b=r=(8in)/(2)=4in\\\\c=h`

("r" is the radius and "h" is the height and "l" is the slant height.)

You need to find "h". Then, solving for "h", you get:

`h=√((7in)^2-(4in)^2)\\h=5.74in`

Then, substituting values into the formula, you get:

`SA = (3.14)(4in)^2 + (3.14) (4in)(7in)=138.16in^2`