Students unlock trigonometry — the sine, cosine, and tangent ratios — discovering how the angles of a right triangle are tied to the ratios of its sides, and using SOH-CAH-TOA to find missing sides and angles.
Students will be able to…
Give me one angle and one side of a right triangle, and I can find every other part. What is the hidden connection between angles and side ratios?
Project this and change the angle. Watch the triangle reshape and the sine, cosine, and tangent ratios update — SOH-CAH-TOA in action.
Tap any phase to open the teacher moves and student actions.
How can one angle unlock every side of a right triangle?
Teacher models.
Class uses the Trig Explorer.
Students solve triangles.
One triangle.
Aligned to the Common Core State Standards for Mathematics (High School: Geometry).
Define trigonometric ratios for acute angles in right triangles.
Explain the relationship between the sine and cosine of complementary angles.
Use trigonometric ratios and the Pythagorean theorem to solve right triangles.
Use similarity criteria (which underlie trig ratios) to solve problems.
Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.
Have students solve angle-of-elevation and depression problems — like finding a building’s height from a distance and an angle. A printable trig sheet is in the Math library.
Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.
A quick self-check with instant feedback, drawn from this lesson’s key terms.
A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.