Download radius (r)

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Agenda
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Questions on homework?
Warm-ups: give examples of the following
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Name an acute angle
Name an obtuse angle
Name a right angle
Name 2 polygons
Name 2 supplementary angles
Name 2 complementary angles
Turn the warm up at the end of the class (put your name on your paper)
Sections 1.5 to 1.9
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Section 1.5 Triangles
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Objectives: Define and classify triangles and their
related parts
A triangle is a polygon with three sides
Classify triangle with angles
 Right
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triangle: a right triangle has one right angle
 Acute triangle: an acute triangle has three acute angles
 Obtuse triangle: an obtuse triangle has one obtuse angles
Classify triangle with sides
 Scalene triangle: a triangle with no congruent sides
 Equilateral triangle: a triangle with three congruent sides
 Isosceles triangle: a triangle with at least two congruent
sides
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More definitions
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For an isosceles triangle, (examples on the board)
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The angle between the two sides of equal length is called the “vertex
angle”.
The side opposite the vertex angle is call the base of the isosceles
triangle.
The two angles opposite the two sides of equal length are called base
angles of the isosceles triangle
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Section 1.6 Special Quadrilaterals
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Quadrilaterals is a polygon with four sides. The
special quadrilaterals are: (examples on the board)
Trapezoid – with exactly one pair of parallel sides
Kite – with two distinct pairs of consecutive
congruent sides
Parallelogram – with two pairs of parallel sides
Rhombus – an equilateral parallelogram
Rectangle – an equiangular parallelogram
Square – an equilateral rectangle; an equiangular
rhombus; a regular quadrilateral
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Section 1.7 Circles
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A circle is the set of all points in a plane at a given
distance from a given point
The given distance is called the radius (r)
The given point is called the center (denoted by a dot)
The segment from the center to the point on the circle
is also called radius.
More examples on the board
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More terms of Circles (1.7)
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Chord – is a line segment whose endpoints lie on the circle
Diameter – is the chord that passes through the center; a
diameter is the longest chord
Tangent – a tangent is a line that intersects the circle at only
one point; that point is called “point of tangency”
Arc – is two points on the circle and a continuous (unbroken)
part between the two endpoints.
Semicircle – is an arc of a circle whose endpoints are the end
point of a semicircle.
Major arc – an arc of a circle that is larger than a semicircle
Minor arc – an arc of a circle that is smaller than a semicircle
Measurement of an arc is the same as central angle which is
the angle with its vertex at the center of the circle, and sides
passing through the endpoints of the arc.
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Section 1.8 Space Geometry
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Space is the set of all points in three-dimension, 3-D
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To draw the 3-D, use isometric drawing, i.e. use dashed line for
edges that further away (the part you can see) and use the solid
line for the part you can see.
Shapes for 3-D that you need to be familiar with are:
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Cylinder
Cone
Prism
Pyramid
Sphere
Hemisphere
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Section 1.9 A picture is worth thousand words
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Translate descriptions into diagram, and vice versa
Geometry is the course that deals with shapes, thus
visualize the shape and translate problems
information into a labeled drawing is essential
Venn Diagram is a diagram that represents larger
groups that contains smaller groups are circles within
the circles, Example: create Venn Diagram with the
shapes: parallelograms, rhombuses, rectangles, and
squares.
Use the Venn Diagram is easy to see the subsets, or
common parts between the subsets
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Homework
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All homework due on Mondays, and place your homework
inside the folder, I will give you the HW log next Monday
HW #5, Section 1-5, page 62-65, #1, 5, 9
HW #6, Section 1-6, page 66-67, #1 – 7
HW #7, Section 1-7, page 72-73, #2 – 9, 11
HW #8, Section 1-8, page 78-79, #1 – 6, 11
HW #9, Section 1-9, page 84-85, #5, 10
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