2. Topic: Trigonometry Ratios

3. Using the Calculator… CAUTION! Always be on Degrees DEG, DG, D NOT Rad or Grad To get the RATIOS: tan, cos, or sin button to get the ratios. To get the ANGLE Press: INV, 2 nd Function or SHIFT to get the sin -1 cos -1 or tan -1 of the ratio.

4. Knowing the Angle and finding Ratio… SIN Sin 34°  ON THE CALCULATOR PRESS THE FOLLOWING… 4 3 = OR SIN = 3 4

5. Finding the Ratios from a Triangle… Remember: SOH CAH TOA Sin : OppCos: AdjTan: Opp Hyp Hyp Adj Label the triangle from angle x (opp, adj, hyp) Find the Ratio: Put the values in the Formula and Divide. Sin x = 3 = 3 ÷ 5 = 0.6000 5 Cos x = 4 = 4 ÷ 5 = 0.8000 5 Tan x = 3 = 3 ÷ 4 = 0.7500 4 Opp Hyp Adj Generally we round to 4 significant figures. 3 4 5 x

6. Finding the Ratios from a Triangle… and then finding the Angle. Remember: SOH CAH TOA Sin : OppCos: AdjTan: Opp Hyp Hyp Adj Label the triangle from angle x Find the Ratio: Put the values in the Formula and Divide. Determine the inverse of sin, cos, or tan. Sin x = 0.6000 Cos x = 0.8000 Tan x = 0.7500 x = Sin -1 0.6000  x = Tan -1 0.7500  x = Cos -1 0.8000  3 4 5 x Opp Hyp Adj