Results 1 to 5 of 5

Math Help - Area of Parallelogram

  1. #1
    Del
    Del is offline
    Member
    Joined
    Nov 2007
    Posts
    83

    Area of Parallelogram

    Find the area of the parallelogram with vertices at and

    Area = ?

    I've found the base vector multiplied by the sidw vector to be , or 50.1996. I need to find the angle between these two vectors.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Behold, the power of SARDINES!
    TheEmptySet's Avatar
    Joined
    Feb 2008
    From
    Yuma, AZ, USA
    Posts
    3,764
    Thanks
    78
    Quote Originally Posted by Del View Post
    Find the area of the parallelogram with vertices at and

    Area = ?

    I've found the base vector multiplied by the sidw vector to be , or 50.1996. I need to find the angle between these two vectors.
    to find the angle between two vectors use the dot product

    v_1=3 \vec i -5 \vec j,v_2=-3 \vec i -11\vec j

    v_1 \cdot v_2=|v_1||v_2|\cos(\theta)

    -9+55=\sqrt{34} \cdot \sqrt{130} \cos(\theta)

    \cos(\theta)=\frac{46}{\sqrt{4420}}

    Check my work as this was done while I was riding a bus without a calculator, but the theory is correct.

    good luck.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,658
    Thanks
    1615
    Awards
    1
    If v_1 & v_2 are adjacent sides of a parallelogram then its area is \left\| {v_1  \times v_2 } \right\|.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Del
    Del is offline
    Member
    Joined
    Nov 2007
    Posts
    83
    Yeah, I'm trying to find the area using two adjacent sides. How do I find the cross product of two vectors on the x-y plane?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,658
    Thanks
    1615
    Awards
    1
    Quote Originally Posted by Del View Post
    Yeah, I'm trying to find the area using two adjacent sides. How do I find the cross product of two vectors on the x-y plane?
    Make the k component zero.
    Example: v_1=3i - 5j + 0k.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Area of triangle in parallelogram
    Posted in the Trigonometry Forum
    Replies: 7
    Last Post: November 24th 2011, 11:42 AM
  2. Area of Parallelogram
    Posted in the Geometry Forum
    Replies: 4
    Last Post: April 16th 2009, 01:58 PM
  3. Area of a Parallelogram
    Posted in the Calculus Forum
    Replies: 1
    Last Post: September 6th 2008, 05:32 PM
  4. area of parallelogram
    Posted in the Pre-Calculus Forum
    Replies: 8
    Last Post: September 6th 2008, 01:50 PM
  5. area of parallelogram
    Posted in the Geometry Forum
    Replies: 1
    Last Post: April 21st 2008, 03:00 PM

Search Tags


/mathhelpforum @mathhelpforum