p. 1
SUM OF INTERIOR ANGLES IN A TRIANGLE,
Problems
1. Triangle ABC is isosceles. Segments AD, DB and BC
have the same length. Determine the measure (in
degrees) of angle CAB.
C
D
A
B
2. Triangle ABC is isosceles. Segments AD, DE, EF, FB
and BC have the same measure. Determine the measure
(in degrees) of angle DAE.
F
C
D
A
E
B
p. 2
3. Find the missing angle measure:
a.
x
x
x-30°
x
+5°
2
b.
x
x+5°
120°
130°
x+5°
x
4. For the following regular n-gons, give the measure of a
vertex angle and a central angle.
a. dodecagon
p. 3
b. decagon
c. 24-gon
d. 48-gon
5. Given are the measures of the vertex angles of regular
polygons. What is the measure of the central angle of
each one?
a.
b.
p. 4
6. Each vertex angle of a regular polygon measures
How many sides does the polygon have?
7. Given are the measures of central angles of regular
polygons. How many sides does each one have?
a.
b.
8. Given are the measures of the exterior angles of
regular polygons. How many sides does each one have?
a.
b.
.
p. 5
c.
9. The sum of the measures of the vertex angles of a
certain polygon is
. How many sides does the
polygon have?
10. The sides of a regular pentagon are extended to form
a five-pointed star (ABCDE). Determine the sum of the
measures of the angles A, B, C, D and E.
D
E
C
A
B
p. 6
11. Same question as above, but in this case the interior
pentagon is not regular.
E
D
A
C
B