Drawing
a n
A ngle
To
draw
an
angle
given
a
specified
measure,
first
draw
a
ray.
Then,
place
the
protractor
over
the
vertex
(endpoint
o f
t he
r ay).
P lace
a
s mall
d ot
n ext
t o
t he
m ark
o n
p rotractor
t hat
r epresents
t he
d esired
a ngle
a nd
then
c onnect
t he
v ertex
t o
t he
d ot
t o
c reate
t he
s econd
r ay.
V erify
y our
a nswer
i s
c orrect
b y
r e-‐measuring
t he
angle
y ou
c reated.
Pie
( Circle)
C harts
Pie
charts
are
circles
that
are
divided
into
wedges
that
represent
data.
Pie
charts
can
be
misleading
if
the
percentages
t hey
r epresent
d o
n ot
e qual
1 00%.
T herefore,
p ie
c harts
c an
o nly
b e
u sed
t o
d isplay
c ertain
d ata.
To
determine
the
relationship
between
the
angle
and
the
percent
it
represents,
the
following
proportion
is
used:
=
100
360
E xample
1 :
A ccording
t o
t he
c ircle
g raph,
w hat
p ercent
o f
s tudents
c hose
m ath
a s
t heir
f avorite
s ubject?
S olution:
M easuring
t he
a ngle
t hat
r epresents
Math
Math.
T his
a ngle
i s
6 1°.
T herefore,
t he
Other
proportion
t o
f ind
t he
p ercent
i s:
61
=
100
360
English
S olving
t he
p roportion
y ields
Science
= 16.9%
History
E xample
2:
If
250
students
were
surveyed,
how
many
s tudents
chose
history
as
their
favorite
c lass?
S olution:
Like
the
previous
example,
measure
the
angle
using
a
protractor,
then
substitute
the
a ngle
i nto
t he
p roportion:
79
=
100
360
S olving
t he
p roportion
f or
x ,
= 21.9%.
U se
a
s econd
p roportion
t o
d etermine
t he
n umber
o f
s tudents
w ho
c hose
h istory
g iven
t he
p ercentage.
21.9
=
100
250
S olving
t his
p roportion
y ields
t he
n umber
o f
s tudents
w ho
c hose
h istory:
5 5
s tudents.