Presentation on theme: "Agenda 1) Bell Work 2) Outcomes 3) Trig Ratio Review"— Presentation transcript:
1Agenda 1) Bell Work 2) Outcomes 3) Trig Ratio Review 4) Introduction to solving triangles using Trig RatiosTablet password: Trig
2Bell Work 2/21 1) Use Pythagorean Theorem(simplify radicals) A) B) 2) Use properties of special right triangles to solve3) Find the sine, cosine, and tangent ratios below:
3Outcomes I will be able to: 1) Use and understand trigonometric ratios in right triangles
49.5 Trig Ratios***Pretend you are standing at angle A
59.5 Trig Ratios Pneumonic Device: If you remember the word SOHCAHTOA, you can remember the trig ratios.SOHCAHTOA stands for:S = Sine O = Opposite / H = HypotenuseC = Cosine A = Adjacent / H = HypotenuseT = Tangent O = Opposite / A = Adjacent
6Examples Sin A = Sin D = Cos A = Cos D = Tan A = Tan D = How do these ratioscompare?Are thesetriangles similar?Why/Why not?
7Examples 2. Find the sine, cosine and tangent of a 45-45-90. Sin A = Cos A =Tan A = = 1What do we know about all right triangles?They are similarNote: Since all triangles are similar, you can simplify any problem involving trig ratios of a to the ratios aboveBCA
8Examples 3. Find the sine, cosine and tangent of A in a 30-60-90 Sin A =Cos A =Tan A =***All are similar so they will have these same ratios
9Examples4) Use a calculator or your chart to find the following to 4 decimal places:***Note your calculator must be in degree mode***Your tablet calculator does not work for these. We will download a new one next weeka) sin 56 =b) cos 84 =c) tan 16 =.8290*Note you must be able toconvert the trig ratio to adecimal to be able to solvefor pieces in the trianglelater on..1045.2867
10Examples 5) Will sine and cosine ever be greater than 1? No Why? Because the legs of a right triangle can never be longer than the hypotenuse. So you are always dividing them by something bigger than what they are.Will tangent ever be greater than 1?Yes, because one leg can be greater than the other.
11Angle of ElevationAngle of Elevation: When you stand and look up at a point in the distance, the angle that your line of sight makes with a line drawn horizontallyWhere is the angle of elevation?Angle of elevation
12Examples1. The angle of elevation from the base to the top of a playground slide is 55º. The slide takes up 10 feet of space horizontally along the ground. Estimate the height and length of the slide.1) Draw Picture:2) Determine what piece you have3) Create trig ratiosCos 55 =Tan 55 =4) Convert trig ratio todecimal5) Solve for variablehypoppadj
13Examples2. You are measuring the height of a tower. You stand 154 feet from the base of the tower and measure the angle of elevation from a point on the ground to the top of the tower to be 38º. Estimate the height of the tower.Which trig ratio do we use?Tan 38 =Solve for the variable
14Examples Picture: What trig ratio do we have? Solve for the variable 3. You stand at the top of a soapbox derby hill and look downwards. The angle of depression is the angle between your line of sight and a line drawn horizontally. The difference between the elevations at the top and bottom of the hill is called the vertical drop. If the vertical drop is 50 feet and the angle of depression is 13º, find the distance d that a soapbox would travel on this hill.Picture:What trig ratio do we have?Solve for the variable