Inside Mathematics
Circles in Triangles
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Virginia Department of Education
Special Right Triangles and Right Triangle Trigonometry
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
CK-12 Foundation
Newton's Method
Does the accuracy of the first guess make a difference down the line? Learners investigate the effects of the iterative process of finding roots, using Newton's Method. By moving the initial guess of a root on a graph, pupils observe the...
Concord Consortium
Orthogonal Circles
Here's some very interesting circles for your very interested pupils. A performance task requires scholars to sketch a pair of orthogonal circles so the centers are the endpoints of one side of a triangle. They draw an additional circle...
CK-12 Foundation
Half Angle Formulas: Half-Angle Formulas
Slide the resource into your lesson plans. Young mathematicians use a slider to move a movie screen to the right position for optimal viewing. Along the way, they learn to apply the half angle formulas.
Curated OER
Circle Proofs
In this circle proofs activity, 10th graders complete 4 different problems that include circle proofs. They respond to each of the questions that deal with circle proofs. Then, students read the given information and use the circle...
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
Why do Stars Rise in the East?
In this stars rise in the east activity, learners use geometry to show how the Earth rotates from west to east and why celestial bodies appear to rise in the east and set in the west. Students draw a figure and label given points in...
Curated OER
Trigonometry Ratios
Learners identify the different angles and sides of a triangle. In this geometry lesson, students identify the six trigonometric ratios. They graph the graph of each trig function and analyze it.
Curated OER
Circles
Tenth graders explore and define the radius and diameter of a circle. In this geometry lesson, 10th graders calculate the circumference and area of a circle using real world objects and shapes. They discuss chords and lines tangent to a...
Curated OER
Triangles
In this triangles worksheet, 10th graders solve 3 extensive informal geometry problems that involve triangles. First, they sketch a triangle, selecting 3 of the sides and constructing 3 midpoints. Students then draw each of 3 medians by...
Curated OER
The Pythagorean Theorem
For this geometry worksheet, 10th graders answer questions about right triangles by identifying the 3 sides of the triangle. They analyze the different shapes of polygons and relate them to right triangles to find the sides using the...
Curated OER
SAT Grid Ins Practice Test 05
For this SAT practice test worksheet, 12th graders answer 10 short answer questions. Questions are from a variety of topics, but mainly ask about geometry concepts. The test is self-scoring.
Curated OER
Trigonometry Applications
In this geometry worksheet, 10th graders solve application word problems involving the use or right triangle trigonometry, including angle of elevation or depression. The one page interactive worksheet contains five questions. Hints,...
Curated OER
Circle Conjectures
Students are given diagrams and are asked to make a conjecture. In this geometry lesson, students make conjectures of circles. They complete a lab activity to reinforce making conjectures. The first activity addresses a common core...
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...
Illustrative Mathematics
Coordinates of Equilateral Triangles
Can it be constructed? The task poses the question whether it is possible to have an equilateral triangle with its vertices located at integer coordinates. Pupils work with their knowledge of trigonometric ratios and the Pythagorean...
Curated OER
Intersecting Lines and Segments of Measures
Mathematicians measure intersecting lines-and circles, and create chords. In this geometry lesson, students explore interrior and exterior chords created by tangent and secant lines. These segments can be inside the circleor outside the...
Curated OER
Solving Intercepted Arcs
Students investigate circles and its arcs. In this geometry lesson, students identify the relationship between an circle and its intercepted arcs. THey identify the central and inscribed angles.
Curated OER
Measurement via Triangulation
Young scholars utilize triangulation techniques to determine altitudes of objects. An altitude locator is constructed and used to determine the height of a building or a tree. Tangent tables and formulas provide the ratio for the formula...
Curated OER
How High did My Rocket go?
Students shoot off a rocket and measure the trig ratios relation. In this geometry instructional activity, students practice using an inclinometer to figure out how high their rockets fly. They measure angles and height and relate it to...
Curated OER
Circle Packing
Students identify different parts and properties of circles. In this geometry lesson, students identify the radius, diameter, semicircle and inscribed angle of a circle. They identify the tangent lines to a circle.
Curated OER
Right Triangles and The Pythagorean Theorem
Students play a game to reinforce concepts of the Pythagorean Theorem. In this geometry lesson, students find the missing angle and lengths of a right triangle. They use properties of trigonometry about sine, cosine and tangent to solve...
Curated OER
Solving Right Triangles
Students investigate the basic trigonometric functions. In this geometry/trigonometry lesson, students explore strategies to solve right triangles using basic trigonometric functions. The lesson includes an application problem in which...