Project Maths
Introduction to Trigonometry
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...
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...
EngageNY
Inverse Trigonometric Functions
Build on the understanding of finding angles using trigonometric ratios. Pupils develop the definitions of inverse trigonometric functions by restricting their domains in the 13th lesson of a 16-part series. They use inverse functional...
EngageNY
Revisiting the Graphs of the Trigonometric Functions
Use the graphs of the trigonometric functions to set the stage to inverse functions. The lesson reviews the graphs of the basic trigonometric functions and their transformations. Pupils use their knowledge of graphing functions to model...
Illustrative Mathematics
Foxes and Rabbits 2
The fox population chases the rabbit population. Groups model the populations of foxes and rabbits with two trigonometric functions. Individuals graph both trigonometric models on the same graph, and then teams determine an explanation...
Curated OER
Access Ramp
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,...
NASA
The Robotic Arm
Working as teams, class members try to rescue an astronaut using the shuttle arm on a TI-Nspire simulation. Teams must determine the different angle measures in order to reach the stranded astronaut.
EngageNY
Special Triangles and the Unit Circle
Calculate exact trigonometric values using the angles of special right triangles. Beginning with a review of the unit circle and trigonometric functions, class members use their knowledge of special right triangles to find the value of...
NASA
The Lunar Lander – Ascending from the Moon
What angle? Groups determine the height of the lunar lander as it ascends from the surface of the moon and calculate the angle of elevation of the lunar lander at specific times and distances. The provided series of questions lead the...
Illustrative Mathematics
Foxes and Rabbits 3
Model periodic populations. Here, in the context of foxes and rabbits, pupils look at graphs of the populations of these animals in a national park over a span of 24 months. Groups analyze the graphs and determine trigonometric functions...
EngageNY
Law of Sines
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...
EngageNY
Law of Cosines
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...
EngageNY
Addition and Subtraction Formulas 2
Knowing the addition formulas allows for the calculations of double and half formulas. The fourth installment of 16 has the class use the addition formula to develop the double angle trigonometric formulas. Using the double formula,...
EngageNY
Addition and Subtraction Formulas 1
Show budding mathematicans how to find the sine of pi over 12. The third lesson in a series of 16 introduces the addition and subtraction formulas for trigonometric functions. Class members derive the formulas using the distance formula...
EngageNY
Modeling with Inverse Trigonometric Functions 1
Where should I stand to get the best view? Pupils use inverse trigonometric functions to determine the horizontal distance from an object to get the best view. They round out the lesson by interpreting their answers within context.