Padhu led an excellent geometry session tonight. If you weren’t able to join us, here’s a question for you to ponder:

Consider a triangle with vertices at (0,2), (3,4) and (4,1).

- What is the area of this triangle?
- Show that the area of the triangle is equal to the following expression. (The expression is plus/minus one-half the determinant of the matrix formed by using the
*x*-coordinates of the points in the first column, using the *y*-coordinates of the points in the second column, and using a value of 1 for each entry in the third column.)

- Why does the determinant formula work?

We spent a fair amount of time discussing the third question, and Padhu did an excellent job of connecting this topic from Algebra II to topics in the middle school math curriculum.

**Next Meeting**

Our next meeting will be **Tuesday, December 13, 5:00-6:30pm**, at the NCTM Headquarters in Reston, VA.

Will you be there? Please fill out this super-quick, one-question poll: **NoVaMTC December Meeting**.

### Like this:

Like Loading...

*Related*