Download 2.5/2.6 Union, Intersection, Polygons

Geometry
Ms. Brinkman
2.5/2.6 Union, Intersection, Polygons
Skills to Acquire
 Determine the union and intersection of sets.
 Recognize and compare triangle characteristics.
Review Problem:
1. The Union of two sets of numbers is the set of all numbers combined.
Example: P = {0, 2, 4, 6, 8}
Q = {1, 3, 5, 7, 9}
P U Q = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
2. The Intersection of two sets of numbers is the set of all numbers common to both sets.
Example: P = {3, 5, 7, 2, 6,1}
Q = {7, 3, 6, 9, 0, 4}
P ∩ Q = {3, 7, 6}
**If figures have no points in common, then their intersection is the empty set
or the null set. That set is written as { } or O .**
3. Define a polygon:
A polygon is a series of connections
between segments that create endpoints.
Name of Polygon
Number of sides
Triangle
3
Quadrilateral
4
Pentagon
5
Hexagon
6
Heptagon
7
Octagon
8
Nonagon
9
Decagon
10
N-gon
n
4. Triangles are polygons that can be defined by their sides, angles or a combination of both.
Type of Triangle
Description of Triangle
Draw it!
No sides (or angles) of a triangle
are congruent.
SCALENE
Two sides (and two angles) of a
triangle are congruent.
ISOSCELES
All three sides of a triangle are
congruent.
EQUILATERAL
All three angles of a triangle are
congruent.
EQUIANGULAR
5. Is an Isosceles triangle equilateral?
No, because there only 2 sides congruent and an equilateral triangle needs three sides congruent
6. Is an equilateral triangle isosceles? Yes, because an equilateral triangle has at least 2 sides
congruent.