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What is the area of a regular octagon with a side of 6.5 and an apothem 5?

What is the area of a regular octagon with a side of 6.5 and an apothem 5?

use the apothem and the side of 6.5 to find the area of that triangle and times it by 8 since an octagon is 8 triangles put together, thus:

5*6.5*0.5 = 16.25
16.25 * 8 = 130

This entry was posted on Wednesday, April 21st, 2010 at 9:21 pm and is filed under area 5. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

4 Responses to “What is the area of a regular octagon with a side of 6.5 and an apothem 5?”

  1. Hi,

    area of octagon = 204

    I hope that helps!! :-)
    References :
    http://www.math-prof.com/AreaVolume/Octagon.aspx

  2. use the apothem and the side of 6.5 to find the area of that triangle and times it by 8 since an octagon is 8 triangles put together, thus:

    5*6.5*0.5 = 16.25
    16.25 * 8 = 130
    References :

  3. A = ½(5)(6.5)(8) = 130
    References :

  4. the mathemagician on April 22nd, 2010 at 4:01 am

    It is not possible to have a regular octagon with a side length of 6.5 and an apothem of 5 !

    You can stick any numbers you want into the formula for the area of a regular polygon

    A = (1/2) a p

    but, that doesn’t mean the polygon must exist in reality.

    You can check that this is impossible using simple trigonometry.

    QED
    References :

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