Scribe Post for May 20, 2010

Hello there, 9-05! Today we started on Chapter 10 which is Circle Geometry. We went straight to 10.1 and started learning or reviewing about circles since I'm sure most of us know something about circles. Chapter 10.1 is about Exploring Angles in a Circle. For this class, we spent our time taking down notes and Mr. B taught us how to find angles.

Circumference - The boundary of or distance around a circle.
Diameter - The distance across a circle through its centre.
Radius - A line segment joining the centre of a circle to the outside edge.

The angles ABC is called a Central Angle.
Central Angle - An angle form by two radii of a circle.
The straight yellow line from A to C is called a chord.
Chord - A line segment joining two points on the circumference of a circle.



Angles ADC and AEC are examples of Subtended Angles.
Subtended Angle: Lying opposite to.
Inscribed Subtended Angle: is equal to half the central triangle.

How do you find the measurement from B to C? Use Pythagoras!
First of all, why do we use Pythagoras? We can use Pythagoras method as long as there is a right triangle to find out the missing side length. Do you see the right triangle? If you flip it over or turn your head upside down, you will be able to see a right triangle. So, the angles AC will be represented as the hypotenuse which is c. And let's say that AB represents a and BC represents b.
a^2+b^2 = c^2
6^2+b^2 = 10^2
36+b^2 = 100
b^2 = 100-36
b^2 = 64
Square root b^2 = Square root 64
b = 8
The missing measurement of the line B to C is 8 cm.

Homework:
Chapter 10 Warm-Up #1
10.1 Textbook
-Practice, all odd
-Apply, all even
-Extend and any 2
10.1 Workbook
10.1 Worksheets

Well, that is all for now folks! (: I hope you enjoyed my post! Keep working hard 9-05! For exams are coming soon and we only got about a month of school left! The next scribe is KIM (:
Okay tootles!