Exercise 91 Page 461

Practice makes perfect

If we multiply a given number of radians by 180^(∘)π, we get the corresponding number of degrees.

7π/6* 180^(∘)/π

MultFrac

Multiply fractions

1260^(∘) π/6π

ReduceFrac

a/b=.a /π./.b /π.

1260^(∘)/6

CalcQuot

Calculate quotient

210^(∘)

Like in Part A, we have to multiply the number of radians by 180^(∘)π to convert it to degrees.

5π/3* 180^(∘)/π

MultFrac

Multiply fractions

900^(∘) π/3π

ReduceFrac

a/b=.a /π./.b /π.

900^(∘)/3

CalcQuot

Calculate quotient

300^(∘)

If we multiply a give number of degrees by π180^(∘), we get the corresponding number of radians.

45^(∘)* π/180^(∘)

MoveLeftFacToNum

a*b/c= a* b/c

45^(∘)π/180^(∘)

ReduceFrac

a/b=.a /45^(∘)./.b /45^(∘).

π/4

Like in Part C, we have to multiply the given number of degrees by π180^(∘) to get the corresponding number of radians.

100^(∘)* π/180^(∘)

MoveLeftFacToNum

a*b/c= a* b/c

100^(∘)π/180^(∘)

ReduceFrac

a/b=.a /20^(∘)./.b /20^(∘).

5π/9

Like in Parts C and D, we have to multiply the given number of degrees by π180^(∘) to get the corresponding number of radians.

810^(∘)* π/180^(∘)

MoveLeftFacToNum

a*b/c= a* b/c

810^(∘)π/180^(∘)

ReduceFrac

a/b=.a /90^(∘)./.b /90^(∘).

9π/2

Like in Parts A and B, we have to multiply the number of radians by 180^(∘)π to convert it to degrees.

7π/2* 180^(∘)/π

MultFrac

Multiply fractions

1260^(∘) π/2π

ReduceFrac

a/b=.a /π./.b /π.

1260^(∘)/2

CalcQuot

Calculate quotient

630^(∘)

Subchapter links

9.1.1 Introduction to Periodic Models p.433-434

9.1.2 Graphing the Sine Function p.438-440

9.1.3 Unit Circle ↔ Graph p.442-444

9.1.4 Graphing and Interpreting the Cosine Function p.447-449

9.1.5 Defining a Radian p.452-453

9.1.6 Building a Unit Circle p.456-457

9.1.7 The Tangent Function p.460-461

Exercise 91 Page 461

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