National Council of Teachers of Mathematics
The Math Forum: Angles of an Octahedron
This question and answer site from The Math Forum with Dr. Math discusses the angle between two adjacent faces of an octahedron. Links are also provided for additional information on related subjects.
National Council of Teachers of Mathematics
The Math Forum: Volume and Surface Area of a Cone Frustum
This question and answer site deals with the derivation of the formula for the surface area for the frustum of a right circular cone.
National Council of Teachers of Mathematics
The Math Forum: Nctm: Lesson Plan: Area and Volume
This lesson plan helps students understand the difference between area and volume. CCSS.Math.Content.3.MD.C.7.a Find the area of a rectangle with whole-number side lengths by tiling it
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Inequalities and Absolute Value
"Dr. Math" responds to a student question regarding how to solve inequalities that involve absolute value.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Solving Polynomial Inequalities
"Dr. Math" responds to a student question on how to find the solution to a polynomial inequality. Dr. Math's solution is found through analyzing the graph of the function.
National Council of Teachers of Mathematics
The Math Forum: Drexel Math Forum: Distance to an Object
Dr. Math offers a way to calculate the altitude of a triangle using only the lengths of the sides of the triangle. He briefly explains how this was used by the Egyptians long ago.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Three Dimensional Plane Diagrams
This site gives a student a tutorial on how to draw various planes. The site includes information on drawing intersecting planes, parallel planes, perpendicular planes, and a line intersecting two parallel planes.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Intersection of Sets
This site responds to an inquiry about what the intersection of sets is. Dr. Math gives an example using cars with certain attributes and then the intersection of these sets.
National Council of Teachers of Mathematics
The Math Forum: Math to Build On: Crossing & Parallel Lines
A definition of parallel lines that draws a comparison to planes and provides drawings for examples.
National Council of Teachers of Mathematics
The Math Forum: Drexel Math Forum: Pythagorean Theorem
Dr. Math explains how to find distances indirectly by using the Pythagorean theorem.
National Council of Teachers of Mathematics
The Math Forum: Suzanne Alejandre's Designs With Circles
In the Islamic culture, circles are considered to be a unit of measurement and the basis for the organization of space. This is illustrated at this site by a series of exercises.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Equation of a Line Parallel to an Axis
Dr. Math gives a short discussion on how to find the equation of a line parallel to an axis (, parallel or horizontal.)
National Council of Teachers of Mathematics
The Math Forum: Mathematics Teacher Bibliography: Circles
A bibliography of articles relating to circles published in the Mathematics Teacher is listed.
National Council of Teachers of Mathematics
The Math Forum: Pictures of Icosahedrons
This site from Dr. Math and the Math Forum provides several links to pictures of icosahedrons. The information is somewhat brief, but worth checking out for a background on the subject.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Proof the Inscribed Angle Theorem
Dr. Math gives a student a hint on how to prove that an inscribed angle is equal to 1/2 the central angle. You should know what the central angle and inscribed angle are to utilize this site.
National Council of Teachers of Mathematics
The Math Forum: Types of Cones
This site from the Math Forum provides Dr. Math as he explains that whether or not a cone has an edge depends on the type of cone. The information is somewhat brief, but factual, and worth checking out on the subject.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Why the Principal Square Root Is Positive
At this site from Ask Dr. Math at the Drexel University, Dr. Math responds to an inquiry about why the principal square root is positive.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: When Is a Slope 0 or Undefined?
At this site Dr. Math gives a discussion on the slopes of lines. The Dr. gives an analogy between the slope of a line and walking up and down hills. The Dr. explores the concept of undefined and zero slopes through his response to a...
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Absolute Value (Real Numbers Rational)
"Dr. Math" reponds to a problem submitted by a student. The problem involves absolute value inequality.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Reversing the Inequality Symbol
"Dr. Math" responds to a student inquiry of why it is necessary to reverse the inequality sign when multiplying/dividing by a negative value.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math Faq, Prism Formulas
This site defines what a prism is and gives formulas for surface area and volume. Contains related links.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: High School Basic Algebra Review
An overview of basic high school algebra topics can be found here. Absolute value, signed numbers, inequalities and equations, mixture problems, and direct and indirect variation are all listed, each with links to questions posed by...
National Council of Teachers of Mathematics
The Math Forum: The Cross Product
This site gives a brief explanation of cross products.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Sphere Formulas
This site from the Math Forum provides the formulas for finding the area and volume of a sphere.