SOLUTION: What is the surface are of a right circular cone if the cone's diameter is 10cm and the lenght is 20cm. HElp please

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Question 47096: What is the surface are of a right circular cone if the cone's diameter is 10cm and the lenght is 20cm.
HElp please
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
First, a right circular cone doesn't really have a "length". Cones have a "height" which is the inside perpendicular distance from the center of its circular base to the vertex of the cone.
Another commonly-referred-to dimension is the "slant height" of a cone which is the distance measured on the outside of the cone, from the circumference of its circular base to the vertex of the cone.
I'll assume that you are refering to the cone's "height" when you ssay its length is 20 cm.
The formula for finding the area of the lateral surface of a right circular cone is:
S+=+pi%2AR%2Asqrt%28R%5E2%2Bh%5E2%29 Where: R = Radius of the circular base and h = the height of the cone.
S+=+pi%2A10sqrt%2810%5E2%2B20%5E2%29 Using pi+=+3.14 as the approximate value for pi
S+=+31.4sqrt%28100%2B400%29
S+=+31.4sqrt%28500%29
S+=+31.4%2822.36%29
S+=+702.13sq.cm (Approximately)