Chapter 5 Trigonometric Functions Section 1 Angles and

Chapter 5 – Trigonometric Functions Section 1 – Angles and Degree Measure

Angle Basics �If you draw an angle on the coordinate plane and the initial side falls on the x-axis, this is called standard position.

Angles �Angles are traditionally measured in degrees. �A full rotation of an angle around the origin results in a 360 degree angle. �EX is 1: Give rotated 2: Give rotated the 5. 5 the 3. 3 measure of an angle that times clockwise. measure of an angle that times counterclockwise.

Coterminal Angles �Angles are coterminal if they would be drawn in the exact same position. �For examples, 30 degrees and 390 degrees are coterminal, because they are separated by 360 degrees. �EX 3: Find one positive and one negative angle that are coterminal with 225 degrees.

Converting Decimals to Minutes and Seconds �Normally, we might write degrees with decimals, such as 135. 62 degrees. �However, it is more common to write angles with minutes and seconds �To find minutes and seconds from decimal degrees: multiply degree decimal by 60 for the minutes and then if there is STILL a decimal, multiply THAT decimal part by 60 for the seconds

Converting Decimals to Minutes and Seconds �EX 4: Convert 15. 735 degrees to degrees, minutes, and seconds. �To convert the other way, divide minutes by 60 and divide seconds by 3600 and add the results to the original degrees. �EX 5: Convert 39 degrees, 5 minutes, and 34 seconds to a decimal rounded to the nearest thousandth.

Assignment �Chapter 5, Section 1 pgs 280 -281 #5 -12, 18 -40 E