Curated OER
Diagonals and Altitudes
Students discover the mathematical way to find the dimensions of a diagonal. Using this process, they complete a worksheet in which they identify the relationships between different degree triangles. They review their answers and are...
Curated OER
Clinometer
Seventh graders build their own Clinometer and using the tangent of angles, estimate the height of trees. Then these students develop and instructional activity to show whole class and determine the tallest tree on school property.
Curated OER
Exploring Geometric Mean
Young scholars solve problems using geometric means. In this geometry lesson, students create altitudes in right triangles. They use Cabri software to move the triangle around and observe different sides and angles.
Curated OER
Exploring Geometric Mean
Student identify the solution using geometric mean. In this geometry lesson, students create right triangles where the altitude of the triangle is the side containing the right angle. They modify shapes using Cabri software and observe...
Curated OER
Using Trigonometry
Fifth graders explore the use of trigonometry to find unknown sides and angles in right-angled triangles, taking the concepts that were developed in the previous unit and looking at different ways of practicing the new skills. Students...
Curated OER
Exploring Centers of Triangles
Students explore properties of triangles using angle bisectors, incenters, circles, midpoints, and altitudes. They use Geometer's Sketchpad in order to create triangles and their properties.
Curated OER
River Width
Middle schoolers determine the level of accuracy needed for computations involving measurements and irrational numbers. They use the correct number of digits in computation to achieve an appropriate unit or level of accuracy when...
CK-12 Foundation
Ck 12: Geometry: Trigonometric Ratios With a Calculator Grades 9 10
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to find trigonometric ratios with a calculator in order to find missing sides of right triangles.
CK-12 Foundation
Ck 12: Geometry: Trigonometric Ratios With a Calculator Grades 8 10
[Free Registration/Login may be required to access all resource tools.] Use a calculator to find trigonometric ratios.
Illustrative Mathematics
Illustrative Mathematics: F Tf Trigonometric Ratios and the Pythagorean Theorem
The purpose of this task is to use the Pythagorean Theorem to establish a fundamental trigonometric identity for an acute angle. The reasoning behind this identity is then applied to calculate a cosine for a given obtuse angle. Aligns...
Illustrative Mathematics
Illustrative Mathematics: G Mg the Lighthouse Problem
For this task, students are asked to calculate the height above sea level of a lamp on top of a lighthouse that is visible to a boat, and to examine two other interpretations of the distance from the lighthouse to the boat. Aligns with...