The Tangent Ratio Geometry 9 1 What are

The Tangent Ratio Geometry 9 -1

What are the values of the unlabeled sides? Review

What are the values of the unlabeled sides? Review

New Material

Working in groups, one for each group • Ruler • Protractor • Calculator • Graph paper Get your supplies Ready

• If we have a 30° – 60° – 90° Triangle, of any size, and know one side, we can calculate the size of the other two sides. • Same for a 45° – 90° triangle • What about other more likely angles? Trig Investigation

• • • Draw one large right triangle Let the angles be 20°, 70° and 90° Label the angles and sides as shown B c A b a C Trig Investigation

• Measure all the sides in millimeters B c A b a C Trig Investigation

• Complete these ratios, using your calculator B c A b Trig Investigation a C

• How do all the groups in the class ratios compare? B c A b Trig Investigation a C

• Is there any significance to these numbers? 0. 94 B 0. 34 c 2. 74 A b Trig Investigation a C

• If the ratios are always the same, we should give them a better name than ratio a over b. What should we call them? Trig Investigation

Trig Definitions

Trig Ratios Sine

Trig Ratios Cosine

Trig Ratios Tangent

SOHCAHTOA There must be a shortcut to remember this. SOHCAHTOA Trig Ratios

Practice Problems

Practice Problems

Practice Problems

Example

Practice Problems

Practice Problems

Practice Problems

Practice Problems

Practice Problems

Practice Problems

Practice Problems

Practice Problems

Practice Problems

• Pages 473 – 475 • 12 – 20 even, 28, 48, 50, 67 - 69 Homework