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How do I find this... Math Help!?

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Here's the Question-

A Cylinder has base radius less than 5 cm.

The Surface Area of the Cylinder is 410 cm(squared).

What is the height, and how did you find it??

Help??

I know the formula for Surface Area, but I can't figure out how to work backwards- HELP!

1 Answer

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  • Anonymous
    1 decade ago
    Favorite Answer

    Surface area should be 2πr²+(2πrh)

    410 = 2π(5)²+(2π(5)h)

    410=2π*25 + (10πh)

    410=50π + 10πh <--- multiply π into equation

    410=157.079633 + 31.4159265*h <--- subtract 157.079... from both sides

    252.920367 = 31.4159265*h <--- divide both sides by 31.4159265 to isolate h

    h = 8.05070533 cm

    ANSWER:

    Because you said that the radius had to be less than 5, I suppose you can't really say what the height should equal, but rather what it must be greater than. So the height must be greater than 8.051 cm (I rounded off the decimal)

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