Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....

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...

The topic of trigonometric ratios is often covered with loads of rote memorization baked into the activity. This activity set, however, leans more on using similar triangles and discovery learning to help young geometers develop a deeper...

Use right triangles for more than just mathematical problems. The first two lessons of a unit ask pupils determine distances between cities by using the Pythagorean Theorem and a map. To cement understanding, learners use trigonometric...

Model geometric concepts through a hands-on approach. Learners apply similar triangle relationships to solve for an unknown side length. Before they find the solution, they describe the transformation to help identify corresponding sides.

Prove the Law of Sines two ways. The ninth segment in a series of 16 introduces the Law of Sines to help the class find lengths of sides in oblique triangles. Pupils develop a proof of the Law of Sines by drawing an altitude and a second...

Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...

Build upon the Pythagorean Theorem with the Law of Cosines. The 10th part of a 16-part series introduces the Law of Cosines. Class members use the the geometric representation of the Pythagorean Theorem to develop a proof of the Law of...

Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...

Your learners combine their knowledge of real and imaginary numbers and matrices in an activity containing thirty lessons, two assessments (mid-module and end module), and their corresponding rubrics. Centered on complex numbers and...

Just about every public building that your students are familiar with has an access ramp which complies with ADA requirements. As it turns out, designing such a ramp is an excellent activity to incorporate slope, the Pythagorean Theorem,...