Interactive Notes Ms. Matthews

 Label it QRS, where R is the RIGHT angle  Which SIDE is OPPOSITE of ANGLE Q?  Which SIDE is ADJACENT to ANGLE Q?  Which SIDE is OPPOSITE of ANGLE S?  Which SIDE is ADJACENT to ANGLE S?

 Look at your triangle QRS  What is the ratio of sine Q?  What is the ratio of cosine Q?  What is the ratio of tangent Q?  What is the ratio of sine S?  What is the ratio of cosine S?  What is the ratio of tangent S?

 Re-draw triangle QRS.  Label QR=21, SR=28, and QS=?  How do you find the length of QS?  What is sine Q?  What is cosine Q?  What is tangent Q?  What is sine S?  What is cosine S?  What is tangent S?

 Draw and label right triangle ABC where B is the right angle  Label AC=34, CB=16, AB=?  How do you find AB?  What is sin C?  What is cos C?  What is tan C?  What is sin A?  What is cos A?  What is tan A?

 Handout #2-10  Homework #11-18

Trig Part 3

 To find an angle, you need 2 sides of the triangle  Look at the sides and determine which trig function you should use  If it doesn’t have the hypotenuse, use tangent  If it has the hypotenuse, sin or cos depending on which angle you need  Set up the proportion. Use the INVERSE operation to find the angle

 Draw and label right triangle ABC where B is the right angle, AB=21 and BC=9  Find the measure of angle A  What information do you have?  What trig function should you use?

 Draw and label triangle QRS where R is the right angle, QS=42 and RS=40.  What is the measure of angle Q?

 Try problems #1-4

 To find the missing side, you need to identify which side is needed  What other information you have  What trig function to use  Set up a proportion and cross multiply

 Draw and label triangle ABC where B is the right angle, angle A = 48º, AB=28, AC=x  What information do we need?  What trig function would be best?

 Try problems #1-4

 When you find the reciprocal of a number, you flip the fraction over.  For example, the number 1/3 would become 3/1 or 4/5 would become 5/4

 We know the definition of the 3 main trig functions  Sine = Opp/Hyp  Cos= Adj/Hyp  Tan= Opp/Adj  What would be the reciprocal of each of these?

 Cosecant = Hyp/Opp  Secant = Hyp/Adj  Cotangent = Adj/Opp

 Sine  COSECANT (CSC)  Cosine  SECANT (SEC)  Cotangent  COTANGENT (COT)

 Cosecant θ= (1/Sin θ)  Secant θ = (1/Cos θ)  Cot θ = (1/tan θ)