Tuesday, May 21, 2013

Finding the surface area of a Cone

How to find the surface area of a Cone

The video works the problem Surface Area of a Cone

 

In order to find the surface area of a cone you add the lateral area plus the base area

The lateral area of a cone equals 1/2 dπ*s  

D = diameter

S = slant height

Base Area = πr^2

Find the surface area of a cone with a diameter of 6 units and a height of 4 units.

Step 1. The radius = ½ diameter = 3 units

Step 2 Find the slant height by using the Pythagorean Theorem a^2+b^2=c^2

Use the height and radius to find the slant height  3^2+4^2=c^2 which equals 9 +16 = 25

√25=5 equals your slant height 

Step 3 Now use 1/2 dπ*s  

1/2 6π*5=3π*5=15π which will equals the lateral area 

Step 4. Find the base area  by using πr^2

π3^2 = π9

Step 5 Add the lateral and base area in order to get surface area

15π+9 π=24π units^2

Check out the Video if confused Surface Area of a Cone