Download ARCS AND CENTRAL ANGLES

Geometry – Kinsey
Unit 10: Circle Theorems
Notes 2
ARCS AND CENTRAL ANGLES
TODAY’S TARGET: I can _____describe_____ a _____circle_____ using correct _____vocabulary_____.
I can find the _____measure_____ of an _____interior_____ _____angle_____ and an _____arc_____.
TERMINOLOGY AND LABELING
circle:
center:
radius:
diameter:
central angle:
pi:
P
A
B
C
arc:
semicircle:
minor arc:
major arc:
R
P
adjacent arcs:
congruent arcs:
S
T
concentric circles:
congruent circles:
circumference:
arc length:
≅
HOW TO… NAME ARCS AND CENTRAL ANGLES
Ex. 1: Name the arc made by the given angle.
a) ∠𝐵𝑄𝐶
b) ∠1
Ex. 2: Name the central angle made by the given arc.
̂
̂
a) 𝑅𝑆
b) 𝐵𝐶
Ex. 3: If an angle is given, name the arc it makes. If an arc is given, name its central angle.
b) major arc for∠𝐸𝑄𝐹
a) ̂
𝑆𝑈𝑇
HOW TO… FIND THE MEASURES OF ARCS AND CENTRAL ANGLES
Ex. 4 Find the measure of the arc or central angle indicated. Assume that lines which appear to be diameters
are actual diameters.
̂
a) 𝑥, 𝑦 = ?
b) 𝑚∠𝐶𝐴𝐷 = ?
c) 𝑚𝐾𝐽𝐼
𝑥
𝑦
Ex. 5 Solve for 𝑥. Assume that lines which apperat to be diameters are actual diameters.
a)
Ex. 6 Find the measure of the arc or central angle indicated. Assume that lines which appear to be diameters
are actual diameters.
̂
b) 𝑚∠𝑈𝑉𝑇
a) 𝑚𝐼𝐽