Curated OER
Exploring Polygons and The Greedy Triangle
Excellent lesson plan! 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 ropes),...
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...
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.
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...
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.
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
Basic Shapes
Students create books about shapes. For this shape lesson, students select a topic such as points, lines, angles, planes, polygons, quadrilaterals, triangles, circles, and polyhedra. In groups, they create an illustrated children's...
Curated OER
Finding Areas of Triangles, Rectangles, and Circles
Students find the areas of geometric shapes. In this geometry lesson plan 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
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
Angles, Triangles, Quadrilaterals, Circles and Related
Students classify angles. In 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
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
Parallelograms and Triangles
In this parallelogram and triangle worksheet, students answer 10 word problems regarding the area and perimeter of triangles and the area of parallelograms.
Curated OER
Triangles and Quadrilaterals
Second graders explore triangles and quadrilaterals. They rotate to various centers in the room to identify and examine triangles and quadrilaterals. After presenting a picture to the class, 2nd graders locate right angles, triangles...
Curated OER
Let's Explore the World of Triangles and Quadrilaterals!
Second graders explore the features of triangles and quadrilaterals. In this lesson on triangles and quadrilaterals, 2nd graders rotate with their group to five different activities all exploring a different aspect of geometry.
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
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
8th Grade Math Classifying Triangles and Quadrilaterals
Eighth graders engage in a lesson that is about classifying polygons with the focus being upon specific triangles and quadrilaterals. They conduct activities using cutouts for kinesthetic learners to help make connections while...
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
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
Geometric Shapes
Students identify polygons. For this geometric shape lesson, students explore the characteristics of polygons. They identify polygons, and classify triangles according to their sides and angles. Students create a poster representing...
Curated OER
I. M. Pei and the Geometry of the NGA
Students compare design elements in neoclassical and modern architecture. They review knowledge of triangles and quadrilaterals and design a geometric pattern using Pei's polygons They create a city plan using a variety of lines and...
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
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...