Monday, Nov 26, 2007

Hey guys!

I know I'm kind of late for my posting but I still got it before next class.

Today, we didn't do mental math, it was a short block. Mr max had a lot to talk about.. I caught most of it anyways.

We learned about....... CIRCLES. =)!

It was a real hard time to keep up with him, but I hope all of you guys listened well!

To start it off .. everyone forget this 3d stuff .. well not forget, just for this unit thinger.

"Everything is happening in a flat surface, forget about anything behind it"

Before I let you look at the diagrams, you'll have to know some new or for some of you, old words.

Vocab!!

"Chord" - - a line segment joining two points on a curve

"Diameter" - - Any straight line segment that passes through the center of the circle and the endpoints are both on the circle

"Tangent" - - one point touching the circle, the line is on the outside of the circle

"Secant" - - a line that intersects two or more points on a curve

"Radii" - - Plural form of radius

"Central Angle" - - the vertex is always the center of the angle name.

"Inscribed Angle" - -vertex is touching the circle

"Arc" - A piece of circle
(major) ;;; associated with central angle >180)
(minor);;; associated with central angle <180)>

(semi-circle);;;associated with central angle = 180)

.. on to the diagrams that should help you with understanding!

I made these on EUKLID and paint =)!

AB is a chord,
so is KE.
KE is a diameter
and HI is a chord also.
CL is not a chord,
it's a radius.
Finally, DG is a tangent
and JF is a secant line.

Remind you of a poem? Haha.

is a central angle,
***notice that 3 letters name angles and
the vertex has to be the middle letter!!***
EIH is an inscribed angle.

Here is a representation of what the different kinds of lines there are.

• Segment, as you can see has no endpoints.
• Line has both endpoints, the circle.
• A ray has just one end point and it is one way.
  

I'm sorry since I didnt get a chance to put those Accelerated math problems on here!.. But, I just couldnt get the diagrams to look right. If this helps any, here are the statements that Mr Max wrote after demonstrating***

"If a central angle and an unscribed angle in the same
circle both intercept the same arc, then the central angle has a measurement of 2wice the unscribed angle."

And!!

"If a diameter of a radius happens to intersect a chord at a perpendicular, then that chord is bisected at the intersector point."
**** the converse is true also..... meaning that "if a chord is bisected by a radius or a diameter then the angle of intersection is perpendicular."

*******29 days till cmass!!!!!!!!!!!!!!!!!!!!!!