SOLUTION: Calculate the area of the triangle with the following vertices: (-8, -2), (-1, -11), and (-1, -2) I tried my best, and got an answer of 31.5 sq units. I just want to know if th

Algebra ->  Matrices-and-determiminant -> SOLUTION: Calculate the area of the triangle with the following vertices: (-8, -2), (-1, -11), and (-1, -2) I tried my best, and got an answer of 31.5 sq units. I just want to know if th      Log On


   

Question 162512: Calculate the area of the triangle with the following vertices:
(-8, -2), (-1, -11), and (-1, -2)
I tried my best, and got an answer of 31.5 sq units. I just want to know if this is correct,and if not, see the steps to come to the correct answer and what it is. I thank you very much for your time!
Found 3 solutions by Fombitz, scott8148, josmiceli:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's graph the points.

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.
.
The area of a triangle is
A=%281%2F2%29%28bh%29
where b is the base, h is the height of the triangle.
From the diagram,
b=7
h=9
A=%281%2F2%29%28bh%29
A=%281%2F2%29%287%2A9%29
A=63%2F2=31.5
Your answer is correct.

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
yes, you are correct

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
First I want to see if any of the 3 lines that
connect these point is either horizontal or
vertical. that will just make the job easier
The pair of points (-1,-11) and (-1,-2) both have
the same x value, which makes the line between
them vertical.
The pair (-8,-2) and (-1,-2) have the same y value,
so the line between them is horizontal.
That means the triangle is a right triangle
The length of the 1st line is just the difference
between -11 and -2, which is 9
The length of the 2nd line is just the difference
between -8 and -1, which is 7
Using the formula A+=+%281%2F2%29%2Ab%2Ah
A+=+%281%2F2%29%2A9%2A7
A+=+63%2F2
A+=+31.5
Same as you got