Texas Instruments
Investigating Segments in a Quadrilateral
Investigate the properties of the shape formed by connecting the midpoints of adjacent sides of a quadrilateral. In this properties of the shape formed by connecting the midpoints of adjacent sides of a quadrilateral lesson, students use...
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.
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
Inscribed Quadrilaterals and Parallelograms
Learners differentiate between inscribed quadrilaterals and parallelograms. In this geometry lesson, students identify the shaped of the polygons when it is inscribed inside of a circle. They calculate the missing angles of the inscribed...
EngageNY
Ptolemy's Theorem
Everyone's heard of Pythagoras, but who's Ptolemy? Learners test Ptolemy's Theorem using a specific cyclic quadrilateral and a ruler in the 22nd installment of a 23-part module. They then work through a proof of the theorem.
Curated OER
What's your favorite pi?
Sixth graders toss popcorn kernels at a 12? circle inscribed in a 12? square. By counting the number of popcorn kernels that land inside the circle and inside the square the students calculate estimates for the value of pi.
Curated OER
Geometry of Triangles - Week 6
In this triangle worksheet, learners 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
Review Geometry - Week 8 (Triangles)
In this triangle worksheet, students use similar figures to find the length of one side of two similar triangles. They find the area of a triangle inscribed in a rectangle. This two-page worksheet contains eight problems.
Curated OER
Investigating the properties of a circle
Students use wax paper to look at different properties of circles such as chords, tangent lines, inscribed angles, and inscribed angles in a semi-circle, as well as finding the center of the circle, and use GSP to investigate cyclic...
Curated OER
Angles and Arcs
Students identify the relationship between angles and arcs. In this geometry lesson, students rotate and move the circle around to create different arcs on the TI-Navigator. They differentiate between major and minor arcs.
Curated OER
Circles and Angles
Learners identify tangents, chords and secants. In this geometry lesson, students graph circles and identify angles created by secant lines, tangent lines and chords.
Curated OER
Relationships Among Arc and Angle Measures in Circles
Students follow the directions on the attached worksheet to construct shapes using Geometer's Sketchpad. To start the lesson, it is suggested that the teacher guide the students through the initial problem. When constructions are...
Curated OER
Exploring Centers of a Triangle: Part 1
Students use problem solving skills, formal geometry, and The Geometer?s Sketchpad. They model and solve two real-world problems by constructing the in center and circumcenter of triangles.