Determine the area of the quadrilateral whose vertices are (1,3), (6,5), (9,1) and (3,-3).

2. Originally Posted by sharkman
Determine the area of the quadrilateral whose vertices are (1,3), (6,5), (9,1) and (3,-3).
HI sharkman ,

THe area would be ,

$
A=\frac{1}{2}\vert\begin {pmatrix} 1 & 6 & 9 & 3 & 1 \\ 3 & 5 & 1 & -3 & 3 \end {pmatrix}\vert
$

Gosh , i have a problem typing matrix . sorry if its a bit messy . Generally , if you are asked to find the areas of triangle or quadrilateral given their vertices, you can do that . DO you know how to get its determinant ?

HI sharkman ,

THe area would be ,

$
A=\frac{1}{2}\vert\begin {pmatrix} 1 & 6 & 9 & 3 & 1 \\ 3 & 5 & 1 & -3 & 3 \end {pmatrix}\vert
$

Gosh , i have a problem typing matrix . sorry if its a bit messy . Generally , if you are asked to find the areas of triangle or quadrilateral given their vertices, you can do that . DO you know how to get its determinant ?
Ok...but I a not familiar with matrices. Is there a way to answer the question using A = h/2(base1 + base2)?

I would need to find base 1, base 2 and the height after graphing the quadrilateral, right?