CK12 - Trigonometry

10. Answerswill vary. Responsesshouldinclude(1) threepairsof congruentanglesand (2) sidesin propor-
    tion, or someothernotionof “scalingup” or “scalingdown”

Vocabulary

Acuteangle An acuteanglehas a measureof less than 90 degrees.

In the diagramshowbelow, linesM and N are parallel,and they are intersectedby

a transversalT. Angles1 and 3 are alternateinteriorangles.Angles2 and 4 are also

Alternate interior angles of

parallellines

alternateinteriorangles.

Two anglesare congruentif they havethe samemeasure.Two segmentsare con-

gruentif they havethe samelengths.

Congruent

Acutetriangle A trianglewith all acuteangles.

Isoscelestriangle A trianglewith two congruentsides,and, consequentially, two congruentangles.

Equilateraltriangle A trianglewith all sidescongruent,and, consequently, all anglescongruent.

Scalenetriangle A trianglewith no pairsof sidescongruent.

Leg One of the two shortersidesof a right triangle.

Hypotenuse The longestside of a right triangle,oppositethe right angle.

Obtuseangle An anglethat measuresmorethan 90 degrees.

Parallellines Linesthat neverintersect.

Rightangle An anglethat measures90 degrees.

Transversal A line that intersectsparallellines.

MeasuringRotation

Learningobjectives

A studentwill be able to:

• Determineif an angleis acute,right,obtuse,or straight.


• Expressthe measureof anglesin degrees,minutes,and seconds.


• Expressthe measureof anglesin decimaldegrees.


• Identifyand drawanglesof rotationin standardposition.


• Identifyquadrantalangles.


• Identifyco-terminalangles.

Introduction

In this lessonyou will learnaboutanglesof rotation,whichare foundin manydifferentreal phenomena.
Consider, for example,a gamethat is playedwith a spinner. Whenyou spin the spinner, how far has it
gone?

You can answerthis questionin severalways.You couldsay somethinglike “the spinnerspunaround 3
times.”This meansthat the spinnermade3 completerotations,and then landedbackwhereit started.