Results 1 to 4 of 4

Math Help - Finding the area of the shaded figure

  1. #1
    Newbie
    Joined
    May 2008
    Posts
    5

    Finding the area of the shaded figure

    Could anyone tell me how to do these two?

    <--- the side numbers are all 5's
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Banned
    Joined
    Nov 2007
    Posts
    54

    Behind the eight ball.

    If your drawing is accurate, no.
    On the other hand,
    if the first is a circle inside an 8x8 square, yes.
    That's 64 - area of circle with radius 4 (area = pi(r^2)).
    or 64-(16)pi.

    The next figure, see reply from earboth before I lead you astray.



    Bye.
    Last edited by Bradley; May 20th 2008 at 12:40 AM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,829
    Thanks
    123
    Quote Originally Posted by scorpio View Post
    Could anyone tell me how to do these two?

    <--- the side numbers are all 5's
    to #2:

    Unfortunately it isn't clear to me which distance is labeled 5:

    1. The side of a square has the length 5. Then the diameter of the circle is

    d^2=5^2+5^2~\implies~\boxed{d=5\sqrt{2}}

    Then the shaded area is calculated by:

    A=A_{circle}-A_{square}=\pi \cdot \left(\frac{5\sqrt{2}}{2}\right)^2 - 5^2 = 25\left(\frac12\pi-1\right)

    2. The length of the radius is 5. Then the inscribed square consists of 4 isosceles right triangles. The shaded area is calculated by:

    A=A_{circle}-A_{square}=\pi \cdot (5)^2 - 4 \cdot \frac12 \cdot 5^2 = 25(\pi-2)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Banned
    Joined
    Nov 2007
    Posts
    54

    Diagonal across a square, diameter of circle.

    Thanks for pointing my mind back to the figure.

    I will be using this to remind me next time I do geometry lessons with my daughter.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Finding the area of the shaded region?
    Posted in the Geometry Forum
    Replies: 2
    Last Post: July 14th 2011, 12:28 AM
  2. Finding the area of the shaded region.
    Posted in the Geometry Forum
    Replies: 4
    Last Post: January 4th 2011, 12:24 AM
  3. finding the shaded area of a triangle
    Posted in the Trigonometry Forum
    Replies: 2
    Last Post: August 13th 2010, 10:54 AM
  4. Replies: 2
    Last Post: March 1st 2009, 10:28 AM
  5. find area of shaded area (yellow)
    Posted in the Geometry Forum
    Replies: 8
    Last Post: September 4th 2007, 08:34 AM

Search Tags


/mathhelpforum @mathhelpforum