Trigonometric Relationships - Lesson Plan
Standard
Ma.912.T.1 Define and use trigonometric ratios, identities, or functions to solve problems.
Benchmark
MA.912.T.1.1 Define trigonometric ratios for acute angles in right triangles.
Learning Target
Students will be able to determine trigonometric ratios using the coordinate plane.
Materials
Computer/chromebook/tablet
Scientific calculator
Introduction/Warm-up
Have students find Sine, Cosine, and Tangent of the following triangle using as the reference angle. 
Students may need a reminder of sine = opposite/hypotenuse, cosine = adjacent/hypotenuse and tangent = opposite/adjacent.
Guided Instruction/Exploration
Using the GeoGebra Applet, have students work with a partner to find three similar triangles in the coordinate plane. Students will record the x, y, hypotenuse, sin(a), cos(a), and tan(a) of each triangle found. Ask students what they notice.
Students may need a reminder of sine = opposite/hypotenuse, cosine = adjacent/hypotenuse and tangent = opposite/adjacent.
Guided Instruction/Exploration
Using the GeoGebra Applet, have students work with a partner to find three similar triangles in the coordinate plane. Students will record the x, y, hypotenuse, sin(a), cos(a), and tan(a) of each triangle found. Ask students what they notice.Guide students to the conclusion that similar triangles have the same cosine, sine, and tangent.
Guided Practice
Using the triangles they found, have students work with their partner to find the three ratios (cosine, sine, and tangent) for each triangle EXACTLY using a as the reference angle. This will require them to find the length of the hypotenuse using the Pythagorean Theorem. Compare their answers with what they found using the applet.
Come back together as a class and complete the attached Practice Worksheet.
Trigonometric Ratio Practice Worksheet
Independent Practice/Homework
Students will complete the following Trigonometric Ratio Homework.
