9'A' Friday 13th

Yesterday when the class started mrs. Saatkamp told us that she was going to give us Thursday's class time to work on the project, remeber the project is due this FRIDAY and we need to turn the geogeobra document and the one in word. Afterwards we checked the h.w on pg. 373 q's 12-20.We solve the ones that most of the people had problem with, this were q's 12, 19, 24 and 29.


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Number 12 : We need to find DC.
Given: EA=12, BC=8, EADB, D and B are midpoints of EC and AC and
angle DCF and BCF are congruent, therefore we can know that GC is an angle bisector.

EA and DB are proportional, meaning that DB is 6 , this allows us to find that FB which is 4.

Now the only thing left to do is cross multiply DC =4.

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Number 19: Find the value of x.

We know that because they are similar triangles. We cross multiply and we get 280-14x=11x. And x=11.2

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Number 24: Find SN.
Given: SV bisects angle ASB, AS=7, AR=11 and SV=9. Triangle ABS~triangle RTS.

Since both triangles are ~ and SV is an angle bisector we can figure out that AS is proportional to SN and SR is proportional to SV. Knowing this we can cross multiply which gives 63= 18SN and finally SN= 3.5

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Number 28: Find the value of x.
Given: both triangles are similar. The perimeter of triangle ABC is 28.


We are first going to find the perimeter of triangle RST by adding all sides, so the formula would be P=10+ x-4+ x-1.5

P=2x + 4.5
Now that we found the perimeter of RST we can cross multiply giving a result of 16x + 36=280 and therefore x= 15.25

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Number 29: find CF and BD.
Given: BF bisects angle ABC and AC ED. BA=6, BC=7.5, AC=9 and DE=9.

First we are going to find CF, we already know that FC is similar to ED so CF= 9-x. To find x we cross multiply so it's and we get 7.5x= 54-6x
13.5x=54
x=4

Since we found the value of x we now need to replace it and CF=5 and BD is 13.5

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After we finished checking our h.w, mrs. Saatkamp gaves us new h.w due Tuesday, the h.w is the review for the test on Wednesday in pg. 388 q's 13-30. Questions 27-30 are similar to the ones that are going to appear in Monday's quiz so she suggested for us to do does questions in class and then if we had any doubts we could ask her and it would had been a good way of revicing for the quiz, instead we all whent into the math lab and worked in our Geogebra project.