January 25, 2012 part 2

History of Pi

Pi is the circumference divided by the diameter of any circle.

Area of a circle is pi x radius squared/

The circumference of a circle is 2 x radius x pi

Central Angle of a Circle

Arc 

Inscribed Angle

The length of the arc is always double the inside angle

Area of a Circle

Finding the radius of a circle when you are given the area

Finding areas of Sectors

Homework:

Area and diameter worksheets on website.

January 25, 2012

Circle Vocabulary

circle

Chord

Chord of a Circle Visual

Circumference

Compass

Radius

Sector
Sector of a Circle Visual

January 11, 2012

Class Review

Constructions (Good Luck!)

The videos below will walk you through how to do each of the contructions we did in class.  Practice doing this!

 Copy a Line Segment

  Copy an Angle

 **Construct a triangle

not the best video, but you get the idea??

This video might be better for construction triangles.

**Construct a triangle when you are given two angles

 and a side

**Construct a triangle when you are given two sides

 and an angle

Construct Parallel Lines

Construct a Perpendicular Bisector

 Construct a Perpendicular Line through a point

 on a line

Construct  a Perpendicular Line through a

point not on a line

Construct an angle Bisector

How to construct

a circumscribed circle 

in a triangle

Constructing Inscribed Circle

January 4, 2012

Activity in the Beckman book: (state your logic, provide needed justification, but the obvious justification)

1. vertical angles are congruent
2. __

3 things that are undefined

1. Point
   What is a point? how big is it? does it have a size? can we measure the size of a point? Can you define a point without using the word point?
2. Line
   What is a line? A line is a series of points.  Since you can't define a point, you can't define a line.  How wide is a line?  You can't measure that.
3. Plane
   You can't measure the depth of a plane.  You can measure the width and height.

Activity - Take pictures of lines, planes and points in the "real world"

Similar -

Two types of comparisons you can make in similar shapes. You can compare corresponding sides, or the dimensions within the shapes.  (You are comparing the ratios)

The angles have to be the same in similar objects.

Two types of questions that you might be asked:

1. Prove that two objects are similar
2. Find a missing side link

Finding the side of similar objects.  (I apologize that some pics are sideways)

Triangle Congruencies

Video that talks about congurent triangles

• SSS (side, side, side)
• SAS (side, angle, side)
• AAS (angle, angle, side)
• ASA (angle, side, angle)
• HL (hypotenuse leg)

Polygon Congruence

video that talks about congruent polygons

Differentiation Lesson Plan (check class syllabus to see requirements)