- #1

BOAS

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- 19

after searching around on the internet about this problem, it looks like it is Cramer's rule that I want to use, though it wasn't shown to us under that name.

My textbook doesn't cover the material required for this problem, so i'd really like to run what I have done past you guys :)

## Homework Statement

The triangle ABC has vertices A(-1,3,0), B(-3,0,7), C(-1,2,3). Find

**AB**,

**AC**,

**CB**.

Find also the area of the triangle, using a vector method.

## Homework Equations

## The Attempt at a Solution

I found the vectors easily enough.

**AB**= -2

**i**- 3

**j**+ 7

**k**

**AC**= -

**j**+ 3

**k**

**CB**= -2

**i**- 2

**j**+ 4

**k**

Area of a triangle = 1/2 base x height

[itex]A[/itex] = [itex]( \frac{1}{2})[/itex] (

**AB**x

**AC**)

I don't know how to make matrices in latex, but I use what looks to me like cramer's rule (we were just told how to do it, as we haven't covered determinants yet) and come to an answer that;

A = -

**i**+ 3

**j**+

**K**

I hope it's clear to you, but if not, if you can show me how to display matrices i'll gladly show the working.

Thanks!