What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't have a height. They create a new formula and then apply it to problems. 

Concepts

trigonometric word problems, trigonometric ratios, area of triangles

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Additional Tags

math

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Instructional Ideas

• Give learners the measure of an angle when going over example one; assign pairs and give them time to develop a plan
• Use white boards when working through problems to check for understanding

Classroom Considerations

• If learners struggle with variable representations, use numbers when developing the area formula
• Lesson is number 32 in a series of 36

Pros

• The lesson takes time to develop the formula instead of just giving pupils the formula to use, allowing them to develop ownership and increase understanding
• Includes an opener, exit ticket, and practice problems

Cons

• None

Common Core

HSG-SRT.C.6 HSG-SRT.C.7 HSG-SRT.C.8 MP1 MP2 MP7