Thursday, Februrary 2, 2012
There won't be class February 9 (Thursday).
Try to turn in your assignments earlier than the day it's due. It's more useful for you to turn it in early because you can do revisions. And it's no fun getting your feedback too late only to realize that the revisions would have been really easy.
GSP:
- Can take notes on GSP (Geometer Sketch pad) with a text box.
- File - Document Options - You can have multiple pages going
- Basically GSP is a place for you to do geometry. You can create geometric properties.
- Objects in GSP are dynamic (create a circle, can move the circle around, can move a point on the circle around to change the radius). Relationships that you create in the program are maintained- you can explore relationships.
- Can draw 4 sides and make it try to look like a rectangle, but it just looks like it. For it to actually BE that object it has to "satisfy the drag test" (when you move part of the shape it maintains the shape you were looking for- move a corner of a square it stays a square).
- What ever you create keeps the geometric properties that you used to create it
- Can highlight everything and clikc "delete" to delete it if you want
- Draw a line, and a point not on it, how to you make a perpendicular?
- Select the point and line, then go to "Construct" then go to "Perpendicular Line"
- How to draw a perpendicular line without the "construct" menu:
- Draw two different circles with center on one point of line, whos circumfrance intersects other line. where those two circuls interect creates a perpendicular
- Is that true?
- Congruent triangles (SSS) gives us that the angles are congruent, then SAS gives us smaller trianlges congruent, gives us that corner angles are 90 degrees so the lines are perpendicular
- We have just proved that for any kite (Kite= 4 sides, two sides next to eachother are same lenght, other two sides next to eachother are same length)
- Can label points by clicking the A button on the side tool bar then clicking the point you want to lable
- Can put tickmarks on lines to indicate same lengths by clicking on "highlightermarker" on side tool bar and then clicking on line to mark. Click multiple times to add more clicks
- Can use that same tool to mark angles. use tool to click on point then drag out to mark angles
- Construct an Equilateral triangle
- Two circles with equal radius, connect centers as one line, then from two centers draw lines to where two circles intesect. gives us equilateral triangle
- Create tool button is last one on side tool bar.
- Select every part of the tool (equilateral triangle sides and points) then click create tool button, go to create new tool
- Create tool button also can show the steps for the tool (show script view)
- Triangle is made up of 6 pieces: 3 sides, 3 angles
- how many pieces do you need to know to know that the two triangles are congruent
- I have a triangle and it has 3 pieces the same as yours, are they congruent? (2 pieces, 4 pieces...)
- We know the SAS... congruencies work, so we know three works, but in the two triangles we are looking at they might not all be next to eachother like the triangle congruencies need...
- Play around in GSP
- Even if one element is the same (one angle, one side) the two triangles aren't necessarily the same
- example: same side length, two differnt triangles
- 2 elements are not enough
- example: same angle and side, but different triangles
- 3 elements are not enought
- We learned a few ways to construct two lines that are the same lenght that change length with eachother
- draw line segment, draw a point not on the line. select line and point
- in menu construct circle by center and radius
- hide circle that is created
- now we have two lines that are always the same lenght no matter how you change them
- The way you construct things determines how you can manipulate them
- Can look at measurements on angles and lines
- for an angle highlight the line segments around the point and the point. then go to measure menu at top and select angle
- for a line segment highlight just the line segment (not points). then go to measure menu and select length
- For homework don't use reflections, use circles and lines.