lesson 1 menu

1. Name the reflected image

of RS in line l.2. Name the reflected image

of ST in line l.3. Name the reflected image

of RWT in line l.4. Find the length of the image of MN under a dilation with

scale factor r = –3 and MN = 9.

5. Find the magnitude and direction of for A(4, 2) and B(–2, –1).

• circle

• center

• chord

• radius

• Identify and use parts of circles.

• Solve problems involving the circumference of a circle.

• diameter

• circumference

• pi ()

Identify Parts of a Circle

A. Name the circle.

Identify Parts of a Circle

B. Name a radius of the circle.

Identify Parts of a Circle

C. Name a chord of the circle.

Identify Parts of a Circle

D. Name a diameter of the circle.

Answer: 9

Find Radius and Diameter

Formula for radius

Substitute and simplify.

Since all radii are congruent, RN = RP.

Answer: So, RP = 2.

Find Radius and Diameter

1. A

2. B

3. C

4. D

A. 6.25

B. 12.5

C. 25

D. 50

1. A

2. B

3. C

4. D

A. 7.25

B. 14.5

C. 29

D. 58

1. A

2. B

3. C

4. D

A. 4.25

B. 8.5

C. 17

D. 85

Find Measures in Intersecting Circles

Find Measures in Intersecting Circles

Answer: 27 mm

Since the diameter of FZ = 5.

Since the diameter of , EF = 22.

Segment Addition Postulate

Substitution

is part of .

Simplify.

1. A

2. B

3. C

4. D

A. 2.5 in.

B. 4.5 in.

C. 6.5 in.

D. 9 in.

1. A

2. B

3. C

4. D

A. 13.5 in.

B. 15.5 in.

C. 13 in.

D. 12.5 in.

A. Find C if r = 13 inches.

Answer: 26 or ≈ 81.68 in.

Find Circumference, Diameter, and Radius

Circumference formula

Substitution

B. Find C if d = 6 millimeters.

Answer: 6 or ≈ 18.85 mm

Find Circumference, Diameter, and Radius

Circumference formula

Substitution

C. Find d and r to the nearest hundredth if C = 65.4 feet.

Find Circumference, Diameter, and Radius

Circumference formula

Substitution

Use a calculator.

Divide each side by .

Answer: d ≈ 20.82 ft; r ≈ 10.41 ft

Find Circumference, Diameter, and Radius

Radius formula

Use a calculator.

Use Other Figures to Find Circumference

Use Other Figures to Find Circumference

The radius of the circle is the same length as either leg of the triangle. The legs of the triangle have equal length. Call the length x.

Pythagorean Theorem

Substitution

Divide each side by 2.

Simplify.

Take the square root of each side.

Answer: 6

Use Other Figures to Find Circumference

So the radius of the circle is 3.

Circumference formula

Substitution

A. A

B. B

C. C

D. D

A.

B.

C.

D.