Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Triangle Altitudes

For Students 9th - 10th Standards
Here at the Math Forum, Dr. Math proves the concurrency of the altitudes of a triangle. Links are provided for associated topics.
Website
National Council of Teachers of Mathematics

The Math Forum: Foci of an Ellipse

For Students 9th - 10th Standards
The question, "If the major and minor axis of an ellipse are given, how do I find the focus points?" is answered at the Math Forum.
Unknown Type
National Council of Teachers of Mathematics

The Math Forum: Markdown Savings

For Students 9th - 10th
This site from the Drexel University contains problems for practicing using percents, using a mock sale as the motif. A link takes you to a model solution.
Activity
National Council of Teachers of Mathematics

The Math Forum: Problems Library Geometry Triangles

For Students 9th - 10th Standards
This site contains a wealth of problems that deal with the basic definitions of medians, altitudes, angle bisectors, and perpendicular bisectors or the defining characteristics of the different types of triangles. There are also...
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Equations of Conics

For Students 9th - 10th Standards
Posed with a student question about equations of conics, Dr. Math provides some insight on the standard form of parabolas, ellipses, and hyperbolas. One example is shown.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Area of a Parabola

For Students 9th - 10th Standards
Dr. Math helps a student find the area enclosed by a parabola and an ellipse.
Handout
National Council of Teachers of Mathematics

The Math Forum: Spreadsheet Basics

For Students 9th - 10th
A simple introduction on how to create a spreadsheet.
Unit Plan
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: A Rectangular Prism

For Students 9th - 10th
This question and answer site discusses whether it is possible to have a retangular prism that has a volume greater than its surface area.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Zero as Denominator

For Students 9th - 10th
Math Forum response which explains why zero can not be the denominator of any rational number.
Lesson Plan
National Council of Teachers of Mathematics

The Math Forum: Measurement: Metric Conversions

For Teachers 3rd - 5th Standards
This lesson plan has a game to help students convert to various linear metric units and learn their abbreviations.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Commutative Property & Division

For Students 4th - 7th
Dr. Math answers a question about the commutative property and division. Does it really work? See what Dr. Math has to say.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Logic Definitions: Inductive & Deductive

For Students 9th - 10th
This site explains what deductive and inductive reasoning is. The site also explains abductive reasoning.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Proving the Pythagorean Theorem

For Students 9th - 10th Standards
This Ask Dr. Math site explains how to prove the Pythagorean Theorem. Dr. Math gives three variations for proving the theorem.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: How Many Points Determine a Parabola?

For Students 9th - 10th
This site discusses how many point determine a parabola and then gives an example of finding the equation of a parabola given the sufficient number of points located on the parabola.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Parabola Given Three Points

For Students 9th - 10th Standards
This site gives a student a hint of how to determine the equation of a parabola when given three points on the parabola. The Dr. only hints at the solution, encouraging thinking on behalf of the student.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Definition of Quadratic Function

For Students 9th - 10th
Dr. Math briefly defines a quadratic function.
Activity
National Council of Teachers of Mathematics

The Math Forum: Drexel University: Example With Rational Root Theorem

For Students 9th - 10th Standards
This site from Drexel University solves a problem of finding the rational roots of a polynomial using the rational roots theorem, also known as the rational zero theorem.
Activity
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Using Interval Notation to Express Answers

For Students 9th - 10th Standards
"Dr. Math" responds to a student question about solving an inequality involving a variable in the denominator.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Centroid: Center of Gravity

For Students 9th - 10th
At this site you will find am online discussion about the centroid of a triangle. The page begins with a discussion of observations leading to the centroid of a triangle. Dr. Math explains the correct findings as well as the errors made...
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Triangle Centers: Etymologies

For Students 9th - 10th
At this page you will find Dr. Math responding to an inquiry about the relevance of the names of each of the special triangle centers.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Characteristics of an Orthocenter

For Students 9th - 10th
Here at The Math Forum, Dr. Math offers interesting properties of orthocenters. Links are provided at the bottom of the page for information on associated topics.
Website
National Council of Teachers of Mathematics

The Math Forum: Ask Dr. Math: Constructing the Orthocenter

For Students 9th - 10th Standards
Dr. Math shows how to construct the orthocenter of any triangle using a compass and straight edge.
Activity
National Council of Teachers of Mathematics

The Math Forum: Fractals

For Students 9th - 10th
This site contains many links to Fractal information where students go to the given links to discover interesting facts about fractals and many mathematical equations that represent a fractal.
Interactive
National Council of Teachers of Mathematics

The Math Forum: "Zero In" Summing to Zero Fraction Game

For Students 9th - 10th
A card game where students compete to lay down cards - each containing fractions - which sum to zero. The game provides practice for the students who have a working knowledge of the operations with fractions.