geometry walkthrough for hardly human
|dw:1515705472716:dw|
the key to this problem is to find the distance from each vertex to the point (1,-2)
|dw:1515705499887:dw|
now, each of these distances get cut into 1/3 of the original length, and the new vertices are drawn this can potentially become difficult to calculate but I do have some short-cuts you can use, based on the pythagorean theorem/triangle proportionality theorem
the bottom side is the easiest since it's exactly 9 units long and it's horizontal so we can simply draw the new line like so:|dw:1515705628309:dw|
the line on the right hand side can be difficult to estimate but we can draw a right triangle instead like so:
|dw:1515705697594:dw|
this triangle is 3 units wide and 9 units tall, which are easy lengths to cut into (1/3) and draw a new line like so
|dw:1515705734456:dw|
we can use a similar principle for the middle line by drawing this triangle|dw:1515705760083:dw|
after cutting these sides into (1/3) we get 2 and 3, and draw a new triangle like so:
|dw:1515705803064:dw|
then simply connect the new triangle like so:|dw:1515705828480:dw|
and the new triangle in black is your dilated triangle
@hardlyhuman
Thank you so much, I really appreciate it.
Would you mind helping me with another, to make sure i got it right?
sure
Thank you
select one corresponding side from each of the two triangles (for example, the bottom leg) |dw:1515706839420:dw|
|dw:1515706845179:dw|
the small triangle leg is (1/4) the length of the old triangle leg (2/8 = 1/4) so the dilation must have been 1/4 we add a negative sign to indicate the change in orientation (reflection across y = x) so -1/4 = your answer
thank you so much! could I run a few more by you please?
sure
Thank you, btw I like your pfp
is this right?
I think the y-coordinate might be a bit off
Okay, could you help me with it please?
first we will calculate (3/5) of the distance between 5 and 19 which is (3/5)*14 then we add that to 5 to get the true coordinate so 5 + (3/5)*14 so i get 67/5
Okay
Sorry so which one would be 67/5?
the y-coordinate
right
and thats the answer for it? sorry im running on 2 hours of sleep right now
your x-coordinate was correct (16/5,67/5) = your answer
awesome, thank you
Is this one right?
for midpoints you will take the average of the x-coordinates, then the average of the y-coordinates x coordinate = (9+2)/2 y-coordinate = (-8-5)/2 then ^ simplify those, using decimals if necessary
okay
would it be (11/2 , -13/2)
good, but they want decimals instead so (5,5,-6.5) is it
*** 5.5
okay, thank you
is this right?
yup good
Is this one?
I'd say GH = MN is not actually true b/c the triangles are similar not necessarily congruent everything else looks ok
thank you
yup good
yup good
i swear this is the last one
yup good
Thank you so much for all your help, I really appreciate it. Hope you have a good day :)
yeah, you too
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