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Maria's Math news - a FREE math newsletter for parents and teachers

May 2013

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Latest from my blog
This is where you'll find the latest happenings, news, & ideas in math teaching

Math teaching videos
My videos at YouTube show you how to teach concepts.
How to help students with multiplication tables?

Worksheets
Various worksheets on TONS of math topics you can generate for free!

Basic operations worksheet generator is updated! Make worksheets for whole numbers or integers - all four operations, including add & subtract or multiply & divide - horizontal or vertical - add a border and/or extra workspace, use a variable, and more.

Curriculum
Advice, reviews, and resources to help you choose a math curriculum!

Online math games, tutorials, and activities
Games you can play online, interactive tutorials, fun math websites and more. Arranged by topic/level for ease of use.

Lessons
Learn how to TEACH concepts or about general concerns in math education.

Reviews
In-depth reviews of math products

Math help & tutoring
A list of free message boards, math help websites, and online tutoring services.

Fun and games
I have two games on my site, plus links to many.

(easy hangman)
(difficult)

The ideas in this geometry lesson are taken from Math Mammoth Geometry 1 book.

Area of triangles
Free geometry lesson plan from HomeschoolMath.net

Note how a triangle is always exactly HALF of a parallelogram. Therefore the AREA of a triangle must be HALF OF THE AREA of the parallelogram.
In these pictures you see the altitude drawn to the triangle. Note how the same altitude would work for the parallelogram, too. Can you figure out the area of these triangles using that information?

The area of a triangle is half of the area of the parallelogram
that has two same sides as the triangle.

The area of a parallelogram is BASE ALTITUDE.

The area of a triangle is therefore half of that, or

BASE ALTITUDE

The horizontal line symbolizes division.

Examples:

Note that the base does
NOT extend to the altitude.
The area is

4 4

Turn your head to see this
situation.
The area is

4 6

Here it is easiest to think
the base being on the "top".
The area is

5 3

7 1/2

Example problem types

1. Find out the area of the following triangles.

[Pictures available in the ebook]

2. On a grid paper, draw 6 different shaped triangles that have the area of 12

3. Remember? This figure is called a ___________________.

Calculate the area of it by finding the area of the two triangles
and the rectangle into which it is divided.


Find the area of the shaded triangle by using the enclosed rectangle and the three white triangles.		Do the same to this shaded quadrilateral.

New! Times Tales is now on DVD!

The fast, FUN, and easy way to learn multiplication. Learn the upper times tales in two sittings using mnemonic stories.

Area of triangles Free geometry lesson plan from HomeschoolMath.net

Example problem types

Area of triangles
Free geometry lesson plan from HomeschoolMath.net