Post on 15-Feb-2016
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10.1 CIRCLES AND CIRCUMFERENCES Ms. Andrejko
VOCABULARY Radius- a segment with endpoints at the
center and on the circle Chord- segment with both endpoints on the
circle Diameter- chord that passes through the
center and has endpoints on the circle Circle- the set of all points in a plane
equidistant from a given point called the center of a circle
Diameter (chord)
chord
radi
us center
MORE VOCAB…. Congruent circles- two circles are
congruent circles if and only if they have congruent radii
Concentric circles- coplanar circles that have the same center
EVEN MORE VOCABULARY A polygon is inscribed in a circle if all of its
vertices lie on the circle A circle is circumscribed about a polygon if
it contains all vertices of the polygon
Circumference:
C = πd
EXAMPLES
1. Name the circle.
2. Name a radius.
3. Name a chord.
PRACTICE
1. Name the circle.
2. Name a radius.
3. Name a chord.
EXAMPLES The diameters of circle L and circle M are 20
and 13 units, respectively, and QR = 4.
4. LQ=
5. RM=
PRACTICE The diameters of ⊙F and ⊙G are 5 and 6
units, respectively. Find each measure. 4. BF=
5. AB=
EXAMPLES Find the diameter, radius, and circumference
of a circle with the given information. 6. r = 21 ft
7. d = 18 cm
8. C = 6π m
PRACTICE Find the diameter, radius, and circumference
of a circle with the given information. 6. r = 17 ft
7. d = 26 cm
8. C = 22π m
EXAMPLES Find the circumference:
9. 10.
PRACTICE Find the circumference:
9. 10.