Transcript 10-6 part 1: Circles and Arcs

10-6 part 1: Circles and Arcs
Learning Goal: Calculate the
measure of central angles and arcs
Circle Vocabulary
Diameter – segment that goes through the
center and has both endpoints “on the
circle”
Radius – segment whose endpoints are
the center and “on the circle”; r = ½ d
Circle Vocabulary cont.
Congruent Circles – circles with congruent
radii
Central Angle – Angle whose vertex is the
center of the circle
Arc Vocabulary
Arc – a fraction of a circle (pizza crust)
Semicircle – half of a circle (3 letter name)
Minor arc – smaller than a semicircle
Named by its endpoints (2 letters)
Major arc - larger than a semicircle
Named by endpoints & another point (3 letters)
EX 1: Naming arcs
Name all minor arcs
Name all major arcs
Name all semicircles
Formulas
Arc Measure = Central angle of the arc
The measure of a semicircle always = 180o
Arc Addition Postulate -
EX 2: Calculating Arc Measures
10-6 part 1 Assignment
Heading: 10-6 part 1 pg 679 #19-26
Circles must be drawn (you only have
to draw 1 circle for problems 19-24)
Work must be shown
Due Monday for periods 1 & 5 and
Tuesday for periods 2 & 7