A web page and interactive applet showing the ways to calculate the area of a parallelogram. The user can drag the vertices of the parallelogram and the other points change automatically to ensure it remains a parallelogram. A grid inside the shape allows students to estimate the area visually, then check against the actual computed area, which is continuously recomputed and displayed. The text on the page gives three different ways to calculate the area with a formula for each. The applet uses one of the methods to compute the area in real time, so it changes as the rhombus is reshaped with the mouse. A companion page is http://www.mathopenref.com/parallelogram.html showing the definition and properties of a parallelogram 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 will look at examples and non-examples of squares and rectangles to determine properties of the two shapes. Students practice drawing the shapes with specific dimensions and building up to is a square also a rectangle and is a rectangle also a square?

Students will look at examples and non-examples of trapezoids and parallelograms to determine properties of the two shapes. Students practice drawing the shapes with specific dimensions and finding the interior angle sum.

A web page and interactive applet showing the definition and properties of a parallelogram. The applet shows a parallelogram where the user can drag any vertex. The other points then move in such a way that the figure remains a parallelogram at all times. A control to hide the details allows a classroom discussion where students can try to infer what the properties are as it is reshaped by the discussion leader. Text on the page has the formal definition and properties of the parallelogram with links to related pages. A companion page is http://www.mathopenref.com/parallelogramarea.html showing the ways to calculate the area of a parallelogram 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.

These logic number puzzles help students develop strong number sense as they work, clue by clue, to identify the digits of the missing number. The mixed-skills clues incorporate even-odd, less than-greater than, operations (sum, difference), multiples of 5 and 10, geometric terms (octagaon, pentagon, hexagon, quadrilateral, trapezoid, parallelogram), money (quarters, nickels) and measurement (cup, pint, quart, gallon). Students must squeeze every bit of knowledge from each clue to eliminate possible digits until they finally identify the missing digits.

Students investigate parallelogram properties to figure out which properties apply to special parallelograms.