Page 148 - Math Course 3 (Book 2)

Circles: Parts and Circumference

Find Measures in Intersecting Circles
MO. 11 - L1b

Circumference, Diameter, and Example

Radius of a Circle

The diameter of ⊙X, ⊙Y, and ⊙Z are 22 millime-
ters, 16 millimeter, and 10 millimeters, respectively.
Let’s Begin Find EZ.

Find Radius and Diameter
X Y Z
Example E F G

Q
P

S R Since the diameter of ⊙X is 22, EF = 22.
Since the diameter of ⊙Z is 10, FZ = 5.

T FZ is part of EZ.

N EF + FZ = EZ Segment Addition Postulate
M
22 + 5 = EZ Substitution
Circle R has diameters ST and QM. If ST = 18,
find RS. 27 = EZ Simplify.

1
r = d Formula for radius
2 Answer 27 mm
1
r = (18) or 9 Substitute and simplify.
2
Your Turn!

Answer 9
Find Radius and Diameter
Circle M has diameters BG and DN. If BG = 25,
Circle R has diameters ST and QM. If ST = 18, If RN find MG.
= 2, find RP.

Since all radii are congruent, RN = RP. A. 6.25
B. 12.5 B D
C. 25

Answer So, RP = 2. D. 50 M F

N G

Answer

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