Curated OER
Tangent Lines and the Radius of a Circle
Your Geometry learners will collaboratively prove that the tangent line of a circle is perpendicular to the radius of the circle. A deliberately sparse introduction allows for a variety of approaches to find a solution.
Curated OER
Inscribing a Square in a Circle
Inscribing a square in a circle brings up a number of interesting geometry topics including triangle congruence and how to prove a quadrilateral is a square. This activity is followed up by finding the area of the square and determining...
Illustrative Mathematics
Slopes and Circles
An upper-level treatment of what is often presented as a basic concept (the right angle of an inscribed circle on the diameter), this activity really elevates the mathematical thought of the learner! Expected to develop formulas from...
Mathematics Vision Project
Circles: A Geometric Perspective
Circles are the foundation of many geometric concepts and extensions - a point that is thoroughly driven home in this extensive unit. Fundamental properties of circles are investigated (including sector area, angle measure, and...
Mathematics Vision Project
Circles and Other Conics
Through a variety of hands-on activities and physical scenarios, this far-reaching unit leads learners through an exceptionally thorough exploration of circles and parabolas as conic sections. Geometric construction techniques are used...
Mathematics Assessment Project
Solving Problems with Circles and Triangles
After completing a task involving examining the ratio of areas of triangles and circles in a given figure, scholars examine sample responses to identify other strategies they could use to solve the problem.
Flipped Math
Chords and Arcs
Congruence breeds congruence. Pupils learn three more circle theorems dealing with congruent chords and arcs. Learners use the theorems to find the measures of chords and arcs in circles by applying previously learned concepts in the...
EngageNY
Rectangles Inscribed in Circles
Putting a rectangular object into a circular one—didn't the astronauts on Apollo 13 have to do something like this? Learners first construct the center of a circle using perpendiculars. They then discover how to inscribe a rectangle in a...
Curated OER
Mixed Review on Formulas & Theorems on Geometry of Circles
In this geometry worksheet, 10th graders review the formulas and theorems on circles. Problems are comprehensive and detailed. The worksheet is eleven pages long and contains nine problems. Not all answers are included.
Flipped Math
Tangents to Circles
Touch a circle once. Individuals watch a video and learn two theorems related to tangents and circles. The pupils then apply the theorems to find missing angle measures and lengths in figures. At the end, they practice their skills on...
EngageNY
The Binomial Theorem
Investigate patterns in the binomial theorem. Pupils begin by reviewing the coefficients from Pascal's triangle. They look at the individual terms, the sums of the coefficients on a row, and the alternating sum of each row. Individuals...
Flipped Math
Unit 11 Review: Circles
Solve problems around a circle. Pupils watch a video that shows how to apply concepts about circles and related angles and segments to find solutions to word problems. Learners then review the different concepts from the unit in...
Curated OER
SuperShapes, Part 1; "Tri"ing Triangles
An outstanding instructional activity on triangles awaits your math scholars. Learners focus on the triangle, which is the strongest of all polygons. They see the role that triangles play in the design of buildings, and learn about...
Curated OER
Pythagorean Theorem
In this Pythagorean theorem worksheet, 9th graders solve and complete 6 various types of problems. First, they find the length of a right-angled triangle's hypotenuse. Then, students determine which triangle is described and explain...
Curated OER
Chords of a Circle
For this geometry worksheet, 10th graders calculate the length of a chord and the distance from the center of a circle or radius. They compare diameter, chords and radius. There are 10 questions with an answer key.
Mathematics Assessment Project
Sorting Equations of Circles 2
How much can you tell about a circle from its equation? This detailed lesson plan focuses on connecting equations and graphs of circles. Learners use equations to identify x- and y-intercepts, centers, and radii of circles. They also...
Curated OER
History / Introduction of Pythagorean Theorem
Learners explore Pythagoras and the history behind his theorem. They work together to solve a proof that is embedded in the instructional activity.
Curated OER
Principles of Square Roots Lesson Plan
Middle and high schoolers investigate all the different places in math that square root is present. In this geometry lesson plan, pupils discuss square roots as it relates to a right triangle and construction. They go over altitude,...
Curated OER
Equation of a Circle
Young scholars write the equation of a circle. In this geometry activity, students check the solution of a coordinate pair by evaluating them. They graph the circle given the equation and radius.
5280 Math
Pythagorean Triples
From Pythagorean triples to the unit circle. Learners use the Pythagorean Theorem to find Pythagorean triples and then relate their work to the unit circle in a fun algebra project. Their discovery that x^2+y^2 is always equal to one on...
Balanced Assessment
Oops! Glass Top
A short assessment asks participants to find the original radius required to replace a table top. The problem provides a hypothetical situation of having a segment of a broken glass table top. Pupils find the radius of the circular top...
EngageNY
Properties of Tangents
You know about the tangent function, but what are tangent lines to a circle? Learners investigate properties of tangents through constructions. They determine that tangents are perpendicular to the radius at the point of tangency, and...
Curated OER
Pythagorean Circles
Students solve problems using smaller steps. In this geometry lesson, students find the diagonals of rectangles and the area of the annulus between two circles. They are given the starting point and the radius.
Curated OER
Three Tangent Circles
In this tangent circles worksheet, students use pi to solve a problem involving tangent circles. This one-page worksheet contains 1 problem. The answer is provided at the bottom of the page.