An interactive applet and associated web page that demonstrate the relationship of the interior and exterior angles of a polygon. The applet shows an irregular polygon where one vertex is draggable. As it is dragged the interior and exterior angles at that vertex are displayed, and a formula is continuously updated showing that they are supplementary. The tricky part is when the vertex is dragged inside the polygon making it concave. The applet shows how the relationship still holds provided you get the signs of the angles right. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the concept of the interior of an angle. The applet shows an angle where the user can drag the points that define it. A free-floating point can be dragged, and any time it is in the interior of the angle it 'lights up' to show that fact. It can be seen that the interior region stretches out to infinity even if the angle is defined by finite-length segments. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the 'Intersecting Chords' Theorem. (When two chords intersect each other inside a circle, the products of their segments are equal.) The applet presents a circle with two chords. Each end of the chord can be dragged. As it being dragged a calculation continuously changes that shows that the products of their segment are in fact equal. The calculation can be turned off for class discussions. The text on the web page gives four different formulae for calculating the area, depending on the initial givens. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the 'Intersecting Secants Theorem'. The applet shows a circle and two secant lines intersecting at a point outside the circle. The secant points and the external point are draggable. As you drag them the secant lines are redrawn and a realtime computation on the applet shows that the product of their segments are always the same. By dragging two secant points together, the Tangent-Secant Theorem is also demonstrated. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that show how to find the intersection of two straight lines, given the equation for each. The applet sows two lines defined by two pairs draggable points. As any point is dragged the equations for the lines are derived and the point of intersection calculated. The web page shows worked examples using various line slopes, equation forms and unusual conditions, such as one line being vertical. The grid, axis pointers and coordinates can be turned on and off. The equation display can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a full description of the concept of the equation of a line, a worked example and has links to other pages relating to coordinate geometry. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

A web page that introduces the concepts behind coordinate geometry. Can be used as a reference for students to learn about the topic when away from class. Has links to other related pages that contain animated demonstrations. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

"Provided below are links to a series of free booklets to assist mathematics teachers of Grades 4, 5, 6.

These books will stimulate interest, competence, and pleasure in mathematics among students. The activities are appropriate for either individual or group work. Collaborative activities allow students to construct their own meanings and understanding. This emphasis, plus the "Extensions'' and related activities included with individual activities/projects, provide ample scope for all students' interests and ability levels. Related "Family Activities'' can be used to involve the students' parents/caregivers.

Each book is intended to occupy about one week of daily classes. However, teachers may choose to take extra time to explore the activities and extensions in more depth. The books have been designed for specific grades, but need not be so restricted. Activities are related to curriculum expectations."

An interactive applet and associated web page that show the behavior of irregular polygons. The applet shows initially an irregular convex polygon. All vertices are draggable and when dragged show that this has no effect on any other vertex. The polygon can be made regular, and the number of sides changed between 3 and 99. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate isosceles triangles (two sides the same length). The applet presents a triangle where the user can drag any vertex. As the vertex is dragged the others move automatically to keep the triangle isosceles. The angles are also updated continuously to show that the base angles are always congruent. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that provide step-by-step animated instructions on how to construct an isosceles triangle with given base and altitude using only a compass and straightedge. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that provide step-by-step animated instructions on how to construct an isosceles triangle with given sides using only a compass and straightedge. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

This task is closely related to very important material about similarity and ratios in geometry.

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Challenge your kindergarteners to math worksheets that will inspire them to learn to be creative as they count by 5s, 10s, learn numbers to 100, and start to add and subtract small numbers. Lots of handwriting number practice and fun math problems to solve in these kindergarten math worksheets.

The resources include: weekly math review booklets, Kindergarten Math Minutes, math worksheets, monthly math challenge booklets, addition, math enrichment, hundreds charts, math facts, number sense, patterns, place value, subtraction, mental math, geometry, ordering, counting, number lines, calendar skills, comparing numbers, color by number, color by addition, color by subtraction, skip counting, number mazes, shape mazes, matching, grids, greater than/less than, and hundreds chart.

An interactive applet and associated web page that show the properties of a kite, (a quadrilateral with two distinct pairs of equal adjacent sides). The applet shows a kite and the user can reshape it by dragging any vertex. The other vertices move automatically to ensure it always remains a kite. The web page lists the properties of the kite. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Students learn about catapults, including the science and math concepts behind them, as they prepare for the associated activity in which they design, build and test their own catapults. They learn about force, accuracy, precision and angles.

Students explore in detail how the Romans built aqueducts using arches—and the geometry involved in doing so. Building on what they learned in the associated lesson about how innovative Roman arches enabled the creation of magnificent structures such as aqueducts, students use trigonometry to complete worksheet problem calculations to determine semicircular arch construction details using trapezoidal-shaped and cube-shaped blocks. Then student groups use hot glue and half-inch wooden cube blocks to build model aqueducts, doing all the calculations to design and build the arches necessary to support a water-carrying channel over a three-foot span. They calculate the slope of the small-sized aqueduct based on what was typical for Roman aqueducts at the time, aiming to construct the ideal slope over a specified distance in order to achieve a water flow that is not spilling over or stagnant. They test their model aqueducts with water and then reflect on their performance.

In addition to the purely geometric and trigonometric aspects of the task, this problem asks students to model phenomena on the surface of the earth.

An interactive applet and associated web page that demonstrate the definition of a line. The applet presents two points and a line that passes through them extending to infinity in both directions. As the points a re dragged the line moves but it is never possible to reveal a line end. See also the entries for line segment and ray. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.