Use your pupils' sense of curiosity to explore the Parallelogram Law. Here is an activity that outlines a complete instructional activity from beginning to end, allowing pupils to follow a conjecture through to the proof stage.

Prove theorems through an analysis. Learners find the midpoint of each side of a triangle, draw the medians, and find the centroid. They then examine the location of the centroid on each median discovering there is a 1:2 relationship....

Students identify different properties of parallelograms. In this geometry lesson, students complete problems that proves the theorems and properties of parallelograms. They graph the different shapes on paper.

Rhombuses, rectangles and squares are have special properties. In this lesson, young geometers investigate and make conjectures about diagonals, angles, and parallel lines of parallelograms. 

Lead the class in a Greek history activity with a geometric twist. Pupils relate a short video about geometric properties to modern-day methods of solving for unknown angles. They discuss parallel line theorems and...

Tenth graders connect the history of geometry to problem solving. In this geometry lesson, 10th graders investigate polygons through hands on manipulatives and solve problems relating to parallelograms and triangles. They calculate the...

Challenge your class to construct a definition for trapezoids. Looking at four examples and four non-examples, students individually create definitions and use them to classify an unknown shape. Allow for small group and whole-class...

Medians, midsegments, altitudes, oh my! Pupils study the properties of the median of a triangle, initially examining a proof utilizing midsegments to determine the length ratio of a median. They then use the information to find missing...

Ninth graders investigate quadrilaterals.  In this geometry lesson, 9th graders examine and classify quadrilaterals using the slope, midpoint and distance formulas.  Additionally, students create various quadrilaterals given...