GEOMETRY HELP PLEASE~!!! Can someone please explain to me how I am supposed to complete this assignment? I know HOW to do it, but I'm confused with the a + b and how exactly to do any of that. Nowhere have I found any example on how to do this. And yes, that is exactly how the bottom of the paper physically looks, nothing is cut off.
https://wca.sooschools.com/media/g_geo_ccss_2014/3/1003l6a.html

Question

GEOMETRY HELP PLEASE~!!!  Can someone please explain to me how I am supposed to complete this assignment? I know HOW to do it, but I'm confused with the a + b and how exactly to do any of that. Nowhere have I found any example on how to do this. And yes, that is exactly how the bottom of the paper physically looks, nothing is cut off. 
https://wca.sooschools.com/media/g_geo_ccss_2014/3/1003l6a.html

anonymous · Answer

attachment

directrix · Answer

Do you have a compass?

anonymous · Answer

Yes.

directrix · Answer

Okay. Let me draw a moment.

anonymous · Answer

Take your time, no rush.

directrix · Answer

Are you doing this with paper and pencil by hand?

anonymous · Answer

Yes.

directrix · Answer

@KelliRovesSkittles
GeoGebra --- okay, so no GeoGebra.


You will need a straightedge. You can use a ruler for that but you are not allowed to measure with the ruler.

directrix · Answer

One last question: are you doing this assignment on a sheet of paper on which the lengths of a, b, and c are already given.

anonymous · Answer

Yes, those are the three line segments at the top of the paper I think..?

directrix · Answer

We're copying the segments a and b onto the working line that is given.
The deal is this: open the compass and get the length of segment a on the compass.
Then, lift the compass and place the "sticky foot" (sharp end) at the beginning of the working line.

directrix · Answer

I place a point on the working line and swing off segment with length a from there. Do not put the sticky foot on the arrow. There is no point there.

anonymous · Answer

Alright, I'm with you so far, that makes more sense than the original explanation.

directrix · Answer

At the right endpoint of the segment a you copied onto the working line, put the sticky foot at the end of a and swing off a segment of length b. You get b with the compass from the giving length. And, be sure to label your work so it is clear which segment in the end has length a + b.

directrix · Answer

Be sure that the construction marks are showing (the arcs). Don't erase any of that or you cannot prove you constructed it.

anonymous · Answer

Thank you so much, that explains a lot, but I'm still confused about the second one with minus sign and the very last one on how exactly to write them.

directrix · Answer

Here's a better diagram of copying a single line segment with a compass. http://www.dgelman.com/graphicorganizers/geometry/constructions/Copy_a_line_segment.pdf

directrix · Answer

For a - b, you will use the compass to mark off a on the working line.
At the right endpoint of a, you will take the measure of b, place the sticky foot on it, and rather than moving forward, you will clip off the length of b from a. I'll sketch a picture.
I am drawing by hand but you must use the compass and straightedge.

directrix · Answer

That drawing is messy. I can make a clearer one if you don't get it.

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