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...

Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...

So many times the characteristics of triangles are presented as a vocabulary-type of lesson, 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 be a...

If both pairs of opposite sides of a quadrilateral are congruent, is the quadrilateral a parallelogram? This task asks learners to determine the answer and to support their answer with a proof. The resource includes a commentary for...

Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...

In this activity, students will explore the properties of the diagonals of various quadrilaterals. They will use a quadrilateral hierarchy chart to examine the relationship between the quadrilaterals.

This resource explores the diagonals of quadrilaterals. The interactive tool allows learners to examine intersecting line segments in a variety of ways. Topics discussed are perpendicular diagonals, congruent diagonals, and bisected...

This resource explores the bisectors of quadrilaterals. The interactive tool allows learners to draw quadrilaterals with perpendicular bisectors, congruent perpendicular bisectors, and congruent bisectors.

[Free Registration/Login Required] Students are given the two diagonals of a kite of rhombus and are to determine the area and perimeter. Click challenge me to answer practice questions and click learn more to watch a video.

In this activity, students will study special types of parallelograms like rhombus and rectangle, and investigate properties related to their diagonals.

In these problems, students are asked to find: point of intersection of two lines; coefficients that make two lines parallel; intersection of diagonals of a quadrilateral; and the point of intersection of three planes.