A#8 (due 1/31)

7.1.3 pg. 347-348 (#28d, 29, 33b&c, 34)

A#8 handout (front)
A#8 handout (back)

See 7.1.3 - Coordinate Geometry for further assistance on the material.

EDIT:

Answer Key

I need help in 7-29b

How do we find the value

Stephanie R. wrote:

I need help in 7-29b

Stephanie R. wrote:

How do we find the value

Hi Stephanie! I'm sorry, I'm in my master's class so I won't be able to record anything or scan anything for you. You're trying to find the measures of the actual angles? You can either do it one of two ways:


1) Draw an altitude down from B to make a right triangle with leg lengths 2 and 1, and do the same drawing an altitude up from D (also making legs 2 and 1). Then use the inverse tangent function to determine the angle. For example:

tan(x) = 2/1
x = tan^-1(2/1)

As it just so happens to be, both of them will be that same value (63.43 degrees).


2) Two angles have the same measurement if they meet and intersect with lines that have the same slopes. So for instance, < A meets with lines that have a slope of 0 and 2/1. < C also meets at two lines with slopes of 0 and 2/1. If they both meet at those same slopes, then they must be reproducing the same exact angle, regardless as to whether you can actually find that actual angle measure.


I hope those make sense! Ask me again if you still have trouble, because I'm sure I could make it clearer (obviously if I could draw it haha). Thanks for asking!

If you could understand my "diagram," I made a quick one for you here:





As you can see, angles x and y are both in right triangles with its opposite side of 2 and its adjacent side of 1, so they'll have the same angle measurement (or ~63 degrees). The other way is just looking at the slopes of BA (2/1) and AD (0) together compared to BC (0) and CD (2/1). Because they are the same slopes at that intersection, they form the same angle. You wouldn't be able to state the measurement based on that information alone, but that is proof enough for me!

Sorry if that sounded weird. I typed that during class and it's hard to multitask sometimes.