Nctm: Illuminations: Angle Sums

This interactive demonstrates how to bisect an angle.

Become comfortable with using both radians and degrees.

Students identify different angles. For this geometry lesson, students identify different properties of triangles. They find the altitude, median and angle bisector.

Students calculate the solution using half angles formulas. In this calculus instructional activity, students identify the different properties of a triangle using trigonometric properties. They identify the mean, altitude and angles of...

High schoolers draw perpendicular bisectors.  In this perpendicular bisectors instructional activity, students identify the perpendicular bisector in a polygon.  They use web tools to create and measure perpendicular...

Learners solve problems involving triangles. In this geometry lesson, students apply properties of triangles to find the missing angles and sides. They identify angles of parallel lines cut by a transversal.

Students identify different parts and properties of circles. For this geometry lesson, students identify the radius, diameter, semicircle and inscribed angle of a circle. They identify the tangent lines to a circle.

Students differentiate between parallel and perpendicular lines. In this geometry lesson, students identify the different angles created by perpendicular lines and parallel lines. They name the angles that are form when parallel lines...

Students solve problems with triangles. In this geometry lesson, students use the properties of triangles to solve problems. They identify the median, altitude and side vs angle relationship.

Students solve problems with isosceles triangles. In this geometry lesson, students identify and use the properties of triangles to solve their problems. They find the median, altitude, and angles to the triangles.