1. SOLID MENSURATION
MATH 005A
Lecture #2
• Angles
a. Forms of angles
b. Systems in Angle Measurement
• Planes / Polygon

2. Angle


3. Forms of Angles
Angles
Measurement
Acute angle
The angle measures less than 90
degrees
Right angle
The angle measures exactly 90
degrees
Obtuse angle
The angle measures greater than
90 degrees but less than 180
degrees
Straight angle
The angle measures exactly 180
degrees
Reflex angle
The angle measures greater than
180 degrees but less than 270
degrees
Circular angle
The angle measures exactly 360
degrees

4. Systems in Angle
Measurement


5. 

6. 

7. 

8. Polygon
A polygon is a closed plane figure formed by line
segments.
 Parts of Polygon
a. sides – or the edge of the polygon, that make up
the polygon.
b. vertices – are the endpoints of each side
c. diagonal – is a line segment joining two nonadjacent vertices of the polygon.
d. interior angle – is the angle formed by two
adjacent sides inside the polygon
e. exterior angle – is an angle that is adjacent to and
supplementary to an interior angle of the polygon.


9. Naming of Polygon
Number of sides
Name of Polygon
3
Triangle or trigon
4
Quadrilateral or tetragon
5
Pentagon
6
Hexagon
7
Heptagon
8
Octagon
9
Nonagon
10
Decagon
11
Undecagon or hendecagon
12
Dodecagon
13
Tridecagon or triskaidecagon
14
Tetradecagon or tetrakaidecagon

10. 15
Pentadecagon or pentakaidecagon
16
Hexadecagon or hexakaidecagon
17
Heptadecagon of heptakaidecagon
18
Octadecagon or octakaidecagon
19
Enneadecgaon or enneakaidecagon
20
icosagon
30
triacontagon
40
Tetracontagon
50
Pentacontagon
60
Hexacontagon
70
Heptacontagon
80
Octacontagon
90
Enneacontagon
100
Hectogon or hecatontagon

11. Side
s
Prefix
and
Sides
Suffix
20
icosa or icosi
kai
+
1
henagon
30
Triaconta
kai
+
2
digon
40
Tetraconta
kai
+
3
trigon
50
entaconta
kai
+
4
tetragon
60
Hexaconta
kai
+
5
pentagon
70
Heptaconta
kai
+
6
hexagon
80
Octaconta
kai
+
7
heptagon
90
Enneaconta
kai
+
8
octagon
9
enneagon