MAFS.912.F-TF.1.3 Lesson Plan Outline 

What are the Florida State Mathematics Standards?

The Florida State Math Standards are standards that were adopted by the Florida Department of Education in July of 2014. These standards made changes to the Common Core Standards that we established in 2010, and are now implemented in classrooms across the state of Florida.

Additional information about Florida State Mathematics Standards can be found here. 
What is MAFS.912.F-TF.1.3?   

MAFS.912.F-TF.1.3 is the specific Florida State Mathematics Standard related directly to discovering the trigonometric functions and properties of special right triangles. The standard is in the domain of trigonometric functions and is the third standard in the cluster.

The full cluster and individual standards can be found here. 

Before the Lesson: Topics to Review
The Unit Circle. Guide students to review their complete unit circle worksheet. If a unit circle worksheet was not completed with the class prior to this lesson, provide students with the worksheet below and spend the lesson explaining what the unit circle is and guide them to fill out angles, radians, and coordinates.


Blank Unit Circle Handout
Completed Unit Circle Handout

Enrichment Activities:

Beginning the Lesson: 

Teacher Instruction

Practicing the Lesson: Student Work

At Home Practice:

Begin the lesson by drawing the two special right triangles on the board (45-45-90) and (30-60-90).


Ask the students what they know about these triangles, and write what they know on the board.

Label the triangles with their standard side measures, for reference see the paper attached. (Draw the triangles on white paper and scan). Encourage students to draw the same triangles on their paper and follow along as it will help with the practice lesson.

After labeling the side measures, explain how with special right triangles the side measures are often shown with the letter x, meaning any value can be assigned to that side.

Take a moment to assign a value for x for both triangles. Work through solving the triangle and finding the sides as a class. This will transition into the practice lesson.

Example of the board for this lesson

The homework assignment for this lesson should cover both the review material and the new material learned.

Assignments can be assigned from the textbook, and it is recommended that there are 3 problems relating to each of the following: Pythagorean theorem, SOHCAHTOA, and Unit Circle. The remaining problems should focus on special right triangles.

Hand out ‘Practicing Special Right Triangle Worksheet’ to the students. Complete the first problem as a guided practice, and then allow the students to work on the sheet as a group (assign groups).

Answer questions and provide guidance as needed.

Special Right Triangles Group Worksheet
In addition to Khan Academy, IXL offers additional practice problems and guided lessons for students to practice.

The definitions of Sine, Cosine, and Tangent. The goal is for students to be able to define what Sine, Cosine, and Tangent are in relation to an assigned theta. To further prompt this process, the pictures below can be drawn on the board (group review), or handed out (individual review), to guide students.


SOHCAHTOA Review Worksheet

Pythagorean Theorem. The goal is for students to find missing sides on a right triangle, with only given two sides, utilizing  . The practice worksheet located below should be handed out and students should attempt to complete the worksheet on their own before reviewing the worksheet and answering questions.


Pythagorean Theorem Review Worksheet
If students are having difficulty at home doing special right triangles, Khan Academy offers an array of videos and practice problems related to the subject.