More than just a worksheet, the resource provides a thorough guide to navigate through the land of parallelograms. Filled with definitions and theorems, the resource supports learners through problems such as proofs and finding missing...

Extend young mathematicians' understanding of area with a geometry lesson on trapezoids. Building on their prior knowledge of rectangles and triangles, students learn how to calculate the area of trapezoids and other...

This amazingly extensive unit covers a wealth of geometric ground, ranging from constructions to angle properties, triangle theorems, rigid transformations, and fundamentals of formal proofs.  Each of the almost-forty lessons...

Unfortunately for young mathematicians, the world isn't made entirely of parallelograms, triangles, and trapezoids. After first learning the area formulas for these common shapes, students apply this new knowledge to...

Investigate the components of vectors and vector addition through geometric representations. Pupils learn the parallelogram rule for adding vectors and demonstrate their understanding graphically. They utilize the correct notation and...

Lead your high school class on a journey through the world of symmetry and reflections as you discuss geometric principles. Pupils differentiate between reflections and rotations, explore rotational symmetry, and investigate how to...

Trace the links between a variety of math concepts in this far-reaching unit. Ideas that seem very different on the outset (like the distance formula and rigid transformations) come together in very natural and logical ways. This...

Get introduced to the idea of square units and how to calculate the area of a parallelogram. The resource provides a visual lesson to measuring different types of this shape and how it relates to square units. 

Take young mathematicians on an exploration of the world of 3-D geometry with this seven-lesson unit. After first defining the terms perimeter, area, and volume and how they apply to the real world, students continue on...

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

Everyone knows that opposite sides of a parallelogram are congruent, but can you prove it? Challenge pupils to use triangle congruence to prove properties of quadrilaterals. Learners complete formal two-column proofs before moving on to...

Find the area of triangles, rectangles, and parallelograms using this metric worksheet.

When algebra and geometry get together, good things happen! Given a system of inequalities that create a quadrilateral, learners graph and find vertices. They then use the vertices and Green's Theorem to find the area and perimeter of...

Explore how lines of symmetry help define different categories of quadrilaterals. Looking at a square, rectangle, trapezoid, and parallelogram, young mathematicians discover that each shape has its own, unique symmetry. Encourage your...

Introducing ... the Transmographer. Young mathematicians investigate translations, reflections, and rotations. The applet lets users perform transformations on triangles, squares, and parallelograms.

I'd like to prove that this learning exercise has a lot to offer. Seven problems using triangles and parallelograms practice the traditional method of a two-column proof. After the learning exercise is some practice problems that...

Construct yourself a winning geometry unit. A set of lessons introduces geometry scholars to constructions and proofs with compasses and straightedges. It also covers triangle congruence through transformations. This is the second of...

Logical thinking is at the forefront of this jam-packed lesson, with young mathematicians not only investigating geometric concepts but also how they "know what they know". Through each activity and worksheet, learners wrestle with...

Young geometers develop one of the fundamental properties of quadrilaterals (connecting side midpoints gives a parallelogram) in this short but thought-provoking exercise. Using a combination of hands-on techniques and abstract algebraic...

Sort this resource into the Use pile. Scholars investigate attributes of quadrilaterals and then use the results to sort and classify the shapes labeling each figure with their properties to justify the classifications.

Face the vertex of two-dimensional shapes and discover what each figure requires as part of its classification. With one shape per slide, learners see what makes each shape special and compare it to others with similar qualities. 

So many times the characteristics of triangles are presented as a vocabulary-type of lesson plan, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must...

Do you view proofs as an essential geometric skill? The resource builds on an understanding of dilations by proving the Dilation Theorem of Segments. Pupils learn to question and verify rather than make assumptions. 

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....