SOLUTION: Could you help me find the total surface area of the following cone? The answer must be left in terms of pi. The length is 4cm. Radius is 3cm.

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Question 1157788: Could you help me find the total surface area of the following cone? The answer must be left in terms of pi. The length is 4cm. Radius is 3cm.
Found 2 solutions by Shin123, MathTherapy:
Answer by Shin123(626) About Me  (Show Source):
You can put this solution on YOUR website!
Do you mean the height of the cone when you say length? The surface area S can be found by the following formula, S=pi%2Ar%2Asqrt%28h%5E2%2Br%5E2%29, where r is the radius and h is the height. Plugging in 3 for r and 4 for h, we get S=pi%2A4%2Asqrt%284%5E2%2B3%5E2%29, which is equal to pi%2A4%2Asqrt%2825%29=pi%2A4%2A5=highlight%2820%2Api%29.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Could you help me find the total surface area of the following cone? The answer must be left in terms of pi. The length is 4cm. Radius is 3cm.
That other person, AS USUAL, is WRONG!! The total surface area is NOT 20pi.
Surface area of cone = Area of circular base + Lateral Surface Area, or pi+%2A+r%5E2+%2B+pi+%2A+rl, with r being radius, and l being slant height.
With r (radius) being 3 cm, if the height is 4 cm, then this represents a 3-4-5 right-triangle with a SLANT height (l) of 5 cm
We then have: