Results 1 to 12 of 12

Math Help - Area and Perimeter

  1. #1
    Member
    Joined
    Jan 2009
    Posts
    98

    Exclamation Area and Perimeter

    I need some help with the following questions concerning area and perimeter:

    1. Calculate the area of a regular hexagon with a side length of 10 cm.
    Would I use A triangle=0.5 X 10 X 5 and then multiply that again by 6?

    2. Calculate the area and perimeter of the following segments:
    a. A segment with a diameter of 20 cm.
    b. A segment, when it is attached to a right angled triangle which has two side lengths of 12 cm.

    3. Calculate the area and perimeter of one part of the yin-yang symbol (so, I guess just the yin part).

    Thank you! Please reply when you can, as soon as possible if possible!
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    I need some help with the following questions concerning area and perimeter:

    1. Calculate the area of a regular hexagon with a side length of 10 cm.
    Would I use A triangle=0.5 X 10 X 5 and then multiply that again by 6?



    A hexagon is six sided so the area would be the sum of the

    areas of six identical triangles. If we call this area A:


    Area of hexagon = 6*A


    We just need to find the area A of one of these triangles.


    A = (1/2)base*height

    The base is the side of the hexagon or 10 inches

    The height is the distance from the center of the hexagon to

    the center of the side and this forms a right triangle whose

    one side is 10/2 = 5 and has a 60 degrees angle so that

    tan(60) = height/5


    height = 5*tan(60) = 5*\sqrt{3}



    A = (\frac{1}{2}\times (10) 5*\sqrt{3} )= 25\sqrt{3}

    Total ~area~ = 6*[25\sqrt{3}] = 150\sqrt{3}



    There is a formula as well


    (no. of sides)(length of a side)^2
    -------------------------------- = AREA of Regular POLYGONS
    (4)tan(180/no. of sides)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    I need some help with the following questions concerning area and perimeter:


    2. Calculate the area and perimeter of the following segments:
    a. A segment with a diameter of 20 cm.
    b. A segment, when it is attached to a right angled triangle which has two side lengths of 12 cm.

    3. Calculate the area and perimeter of one part of the yin-yang symbol (so, I guess just the yin part).

    Thank you! Please reply when you can, as soon as possible if possible!
    2) & 3) I will help you when you will show your work & where you got stuck
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Member
    Joined
    Jan 2009
    Posts
    98
    Thank you so much!

    I really don't know... But here is my attempt:

    2a. Asegment = Asector - Atriangle

    2a. 60/360 X Pi X 8^2 - 100 (1/2 bh)
    = ?

    I really don't understand this - and would 3 be half of Pi?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    Thank you so much!

    I really don't know... But here is my attempt:

    2a. Asegment = Asector - Atriangle
    2a) that's the right way

    If you want a formula see this



    Put the data that you have with you, its not the real question that you supplied us

    b) 2ways of doing it (try drawing diagram)

    The right angle can be made at center of circle & at circumference

    3) A very simple approach is that since both the colors are symmetrical, the area will be half of the circle

    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Jan 2009
    Posts
    98
    I actually did figure out the yin-yang before you mentioned!!

    How do I find the perimeter of a segment after I have found the area?
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    I actually did figure out the yin-yang before you mentioned!!

    How do I find the perimeter of a segment after I have found the area?
    For perimeter, I think you will have to do

    - Join the diameter from top to bottom of the figure I gave

    - This will approximately form


    • 2 black & white semicircle on either sides
    • each semicircle of a color has the opposite color semicircle
    • the smaller semicircle has radius half to that of the complete circle

    So the perimeter of a single part(black or white) is

    Half of Bigger circle perimeter + total perimeter of the smaller circle (as 2 semicircle on each sides)

    So ultimately
    it will be= perimeter of the Bigger circle
    Follow Math Help Forum on Facebook and Google+

  8. #8
    Member
    Joined
    Jan 2009
    Posts
    98
    Sorry, I meant what would the perimeter of 2 be?
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    Sorry, I meant what would the perimeter of 2 be?
    No problem, it seems I misread

    everything you want to know
    Follow Math Help Forum on Facebook and Google+

  10. #10
    Member
    Joined
    Jan 2009
    Posts
    98
    Oh, what a bugger! For you and me!

    So is the formula for perimeter of a segment on this page?
    Follow Math Help Forum on Facebook and Google+

  11. #11
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by JadeKiara View Post
    Oh, what a bugger! For you and me!

    So is the formula for perimeter of a segment on this page?
    You want arc length its there , you want chord length its there
    .......
    Follow Math Help Forum on Facebook and Google+

  12. #12
    Member
    Joined
    Jan 2009
    Posts
    98

    Smile Mission Completed

    Thank you ADARSH!

    I must go to bed now - so shall we meet again!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. perimeter and area
    Posted in the Calculus Forum
    Replies: 2
    Last Post: August 18th 2010, 03:50 PM
  2. Perimeter and Area
    Posted in the Geometry Forum
    Replies: 3
    Last Post: February 10th 2010, 03:19 PM
  3. Perimeter Area
    Posted in the Geometry Forum
    Replies: 8
    Last Post: October 5th 2008, 07:58 AM
  4. Area from perimeter is it possible?
    Posted in the Geometry Forum
    Replies: 6
    Last Post: July 20th 2008, 05:25 AM
  5. Area and Perimeter
    Posted in the Algebra Forum
    Replies: 3
    Last Post: October 10th 2007, 02:06 AM

Search Tags


/mathhelpforum @mathhelpforum