S.o.s. Math: Double Angle and Half Angle Formulas

We know theorems about circles—now what? Class members prove a theorem, with half the class taking the case where a point is inside the circle and half the class taking the case where a point is outside the circle. The lesson plan then...

Three letter-sized mini posters can be displayed in your elementary geometry class when teaching about angles. One provides information about degree measurement and additive properties, and the other two define acute, right, obtuse,...

Right angles, acute angles, obtuse angles, central angles, inscribed angles: how many types of angles are there? Learners first investigate definitions of inscribed angles, central angles, and intercepted arcs. The majority of the...

In need of a practice worksheet solving quadratic equations using the formula? Have no fear, we have one for you! This worksheet provides the formula at the top with 14 questions following using a variety of leading coefficients. 

Put on your thinking caps because middle school math has never been more interesting in this huge resource full of thought provoking questions. Written as a newsletter, the resource has 10 two-page newsletters with a variety of...

Half at one end becomes proportional on the other. As part of a basic geometry playlist, the video introduces the Angle Bisector Theorem. The presentation uses the theorem to find missing lengths in triangles.

A motivating activity is coupled with the use of algebra to explore the process of identifying the value of an angle. It feels like magic when Sal shows the solution to the final problem. Also, it would be worthwhile to consider using...

While exploring the concept of transversals, Sal discusses corresponding angles, congruent angles, and opposite/vertical angles. He provides a thorough summation of these mathematical concepts. It is the first installment in a series...

Cut it in half with a compass and straightedge! Using construction tools, a video shows how to create an angle bisector. The presenter points out what it means to bisect an angle in terms of the measure and distances from the sides of...

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.