Trigonometry of 2D Shapes
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Objective
I can apply the sine, cosine, and area rules to solve problems involving two-dimensional shapes.
Part 1 of 3
Key concepts
3 concepts
- 1
For non-right-angled two-dimensional shapes, advanced trigonometric tools like the Sine Rule, Cosine Rule, and Area Rule are used.
- 2
The Sine Rule is applied when given two angles and a side or two sides and a non-included angle, while the Cosine Rule is used when two sides and the included angle or all three sides are known.
- 3
To calculate the area of a non-right-angled triangle, the Area Rule is employed, using the formula Area = 0.5ab sin C and requiring two sides and the included angle.
Part 2 of 3
Practice
12 questions
When is the Sine Rule typically used to solve for unknown parts of a triangle?
Under what conditions would you apply the Cosine Rule instead of the Sine Rule?
Part 3 of 3
Exit ticket
Quick comprehension check
“In triangle ABC, side AB measures 7 cm, side AC measures 9 cm, and the angle ∠BAC is 60°. Calculate the length of side BC. Show your work.”
Sample answer included in the free materials
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Teacher Guide
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