Tuesday, November 14, 2006
posted by kimberley at 6:04 PM
Today's class: The first 20 minutes were spent finishing our test from yesterday, "Rational Exponents & Radicals". As a reminder, our units were also due (10% deduction for everyday that it is late). Afterwards we started our new unit, which is going to be a mixture of Trigonometry and Geometry, beginning with Trigonometry.

Trigonometry is basically the computational component of geometry (to get technical), but to keep it within simpiler terms, it has to do a great deal wtih triangles and to start off our unit that is exactly what we created. In our groups, we were asked to make 3 right triangles with angles of 17degrees, 39 degrees and 54 degrees.

How do we create triangles?
let us use the example of c
reating a right triangle with a 17 degree angle.
STEP 1: On your piece of paper, use a ruler to make a straight horizontal line. (view image for further detail)




(To view image, hold shift and click on box)
STEP 2: Using a protractor, place the 90 degree point on one of the ends of your horizontal line.
Make a mark at the top and draw a straight vertical line going down from your mark to
the end point of your horizontal line. (vi
ew image for further detail)



(To view image, hold shift and click on box)
STEP 3: Place the protractor at the 90 degree point on the other end of the horizontal line. Make a
mark at the degree indicated in the instructions (in this case 17 degrees). Then draw a
line from the mark you've made to the end of the horizontal line.
(view image for further
detail)



(To view image, hold shift and click on box)
STEP 4: Label the vertex with its degree (which happens to be 17 degrees in this case). (view
image for further details).



(To view image, hold shift and click on box)

After we were done making our triangles, we labelled the sides with hypotenuse, adjacent and opposite.

REVIEW: Hypotenuse - this is always the longest side, opposite of the right angle.
Adjacent - the side next to the angle
you are refering to.
Opposite - the side opposite of the angle you are refering to .
* (depending on which angle you are refering to, the adjacent and opposite may change)

View diagram:




(To view image, hold shift and click on box)

The last thing we did was divide the sides as follows:
1. opposite/
hypotenuese
2. adjacent/
hypotenuese
3. opposite/
adjacent
(round to 3 decimal places)


Still unsure about how to label a triangle? Then maybe this site will help, take a look.

Oh and btw, tomorrows blogger is Haiyan.



















 



1 Comments:


At November 15, 2006 11:40 PM, Blogger Ms. Armstrong

Hi Kim,
Great explanation for constructing a triangle with exact angles. Could you please edit the diagram showing how to place the protractor to create a 17 degree angle. It is not accurate. Make sure the 0 degree line is ontop of your line, (not the bottom of the protractor). Otherwise several degrees are not being accounted for. Otherwise... a fabulous review of trig functions :)