Question

What is the surface area of the cone? (Use 3.14 for π.)

Answer 1

Answer: 117.226666667 cm^3

Explanation:

So, we all know the formula for working out the volume of a cone is

V= 1/3πr^2h

V = 1÷3 x 3.14 × r^2 x h

The radius is half the diameter. Your diameter is 8 so the radius would be 4. And 7 is your height by the way.

So let's plot it all in!

V= 1÷3 x 3.14 × 4^2 x 7

V = 117.226666667cm^3

Round to the nearest 10 = 117.2cm^3

To the nearest 100 = 117.23cm^3

To the nearest whole number = 117cm^3

Answer 2

Surface area = 87.92 Sq Inch and Total surface area =138.16 Sq Inches

Explanation:

Here we are required to find the surface area of a cone, The formula of surface area of a cone is given as under

r=4

l = 7

`S_(s)=\pi*r*l`

`S_(s)=3.14*4*7`

`S_(s)=87.92`

Also the total surface area is given as

`T_(s)=\pi*r^(2) + \pi*r*l`

We are given

Now we put the values of r and l in main formula

`s=\pi*4^(2) + \pi*4*7\\s=3.14*16+3.14*28\\s=50.24+87.95\\s=138.16`

Hence the Surface area is 87.92 sq inches and Total surface area of the cone is 138.16