Curated OER
Varieties of Quadrilaterals
Learners classify quadrilaterals, In this quadrilaterals lesson, students watch a video about parallelograms, discuss the different types of quadrilaterals, and complete a worksheet classifying quadrilaterals.
Curated OER
Exploring Polygons and The Greedy Triangle
Excellent instructional activity! Anne Linehane's geometry story, The Greedy Triangle, offers an opportunity to practice forming various types of polygons with your learners. Using elastic bands (or Chinese jump...
Illustrative Mathematics
Right Triangles Inscribed in Circles II
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...
Everyday Mathematics
Mathematics Within: Slope and Triangles
Learners discover a method for determining the slope of a line by creating and comparing similar triangles. They fold coordinate grids to make three similar triangles then measure the sides to compare the relationships between the...
Virginia Department of Education
Exploring Quadrilaterals
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.
Curated OER
Triangles
Students identify triangles in the real world and construct their own triangle using drinking straws. They explore abstract triangles and find additional geometric shapes such as trapezoids. Students discuss similar shapes and examine...
Curated OER
Angles, Triangles, Quadrilaterals, Circles and Related
Students classify angles. For this angles lesson, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a manipulative...
Curated OER
The Quirky Quadrilateral
Fourth graders identify and classify different triangles and quadrilaterals. Then they demonstrate an understanding of plane and solid geometric objects and use this knowledge to show relationships and solve specific problems. Students...
Curated OER
Geometry of Triangles - Week 6
In this triangle worksheet, students explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
Curated OER
Investigation - Square Numbers and Triangle Numbers
Fifth graders investigate growth patterns using blocks. In this square and triangle numbers lesson, 5th graders predict sizes of larger triangles and squares based on numerical patterns they observed while building.
EngageNY
Cyclic Quadrilaterals
What does it mean for a quadrilateral to be cyclic? Mathematicians first learn what it means for a quadrilateral to be cyclic. They then investigate angle measures and area in such a quadrilateral.
Curated OER
Squares, Rectangles, and Right Triangles
Youngsters identify and draw polygons including squares, rectangles, and right triangles. In this polygons lesson plan, everyone draws these shapes that have right angles in their math journals.
Curated OER
Sea Squares
In this sea squares worksheet, 10th graders solve 5 different problems that include various geometrical figures. First, they draw a number line using one color. Then, students draw 2 obtuse angles and 3 isosceles triangles with different...
Curated OER
Developing Formulas for Triangles and Quadrilaterals
In this geometry worksheet, 10th graders determine the area of triangles, parallelograms, trapezoids, kites, and rhombuses. The one page worksheet contains eleven problems. Answers are included.
Curated OER
Shape Up
Middle schoolers explore differents types of triangles and quadriaterals. In this polygon lesson, students model identify and compare two and three dimensional geometric figures. Middle schoolers create tangrams and discover the...
Curated OER
Midsegments of Quadrilaterals
High schoolers explore the concept of quadrilaterals as they find the midsegments of quadrilaterals using Cabri Jr. on a graphing calculator. They find midpoints, slopes, angles, and distances of lines and angles.
Curated OER
Exploring Characteristics of Triangles
Young scholars draw triangles and explore the classification of each using the measures of interior angles and lengths of sides. They investigate the sum of the interior angles of various triangles and conjecture and prove the theorem:...
Curated OER
Symmetries of a Quadrilateral I
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...
Curated OER
Investigating Area Relationships
Learners investigate the area of various figures. They construct triangles and quadrilaterals using Cabri Jr. and discuss the relationships between different angles, side lengths, and figures.
EngageNY
Properties of Parallelograms
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...
Curated OER
Finding Areas of Triangles, Rectangles, and Circles
Students find the areas of geometric shapes. In this geometry lesson students find and measure the sides, perimeters, and areas of quadrilaterals, triangles, and circles. Students relate the measures to the others by using formulas.
Curated OER
Quadrilateral Attributes
Students classify quadrilaterals. In this quadrilateral lesson, students identify the characteristics of quadrilaterals. They write their findings in a journal. Students use geoboards to create quadrilaterals from given descriptions.
Curated OER
Triangle Island
Students calculate the altitude of triangles. In the web based lesson plan, students explore the interior distance from a given point in a polygon to its side. They compute the sum of these lengths. Students read life...
Curated OER
Does the Area of the Quadrilateral Change?
Students study area and quadrilaterals. In this multiplication and area activity, students use Polystrip models to change rectangles to form different parallelograms. Students find the area of the models use a Geometer Sketchpad to find...