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#1501 Re: Help Me ! » Side-Angle-Side » 2013-03-25 02:12:18

Check this out.
http://www.math.washington.edu/~king/coursedir/m444a03/notes/congruence%20html/tri-congruence-summ.html
That includes proof for the congruence criterias.

#1504 Re: Help Me ! » Side-Angle-Side » 2013-03-25 01:58:40

Well if we have a perpendicular bisector as the diagonal, then by SAS we can see that they are congruent.

#1506 Re: Help Me ! » Side-Angle-Side » 2013-03-25 01:54:48

Oh okay then. So because the sides and angles coincide (ABC and DEF) making them congruent, that would be a valid proof for Side-Angle-Side? Anyways, thank-you both.

#1507 Re: Help Me ! » Side-Angle-Side » 2013-03-25 01:51:41

For example, to prove Side-Side-Side, using Side-Angle-Side, we just make two triangles such that they make a kite (being diagonal). That proves that the triangles are congruent.

#1510 Re: Help Me ! » Side-Angle-Side » 2013-03-25 01:30:53

Well isn't SAS just an axiom? How do you prove that: If 2 sides and angles in a triangle are congruent to two sides and angles of another triangle, the triangles are congruent. Like take 2 triangles: ABC, DEF. If AB=DE, AC=DF and angle A = angle D, the triangles ABC and DEF are congruent.

#1513 Re: Help Me ! » Side-Angle-Side » 2013-03-25 01:11:06

So I was just wondering, is there a proof to SAS?

#1514 Re: This is Cool » New 17-million-digit Mersenne prime discovered » 2013-03-25 01:06:53

According to NewScientist, Cooper will recieve $3000.

#1515 Help Me ! » Side-Angle-Side » 2013-03-25 00:56:49

ShivamS
Replies: 17

Yesterday, our prof. asked me to name the criterion for triangle congruences which I did. Then he asked me to provide the proof for them which I also did (except SAS of coufrse). He then scolded me and replied that there is a proof for SAS. Until then I was pretty sure that it was an axiom which we use to prove the other criterias.

#1516 Re: This is Cool » Exploring mathematicians and smart mathematicians » 2013-03-25 00:43:53

Some physics professor that must have been. This year the class average for the midterm has been 64% for which my teacher was extremely mad at. The weird thing is, he behaved slightly better with the students in the mid-70%s rather then my friends and I who were in the 90%s range. That would mean he preferred the experimental learners then the conceptual ones.

#1517 Formulas » Calculating day of the week » 2013-03-25 00:32:13

ShivamS
Replies: 1

I recently saw videos of Arthur Benjaman (the "Mathemagician") and saw him calculate day of the week in 3 seconds given the date and month. I checked out Zeller's congruence and then found an algorithm which isextremely simple.
http://www.gregmiller.net/astro/dow.html

#1518 Re: This is Cool » New 17-million-digit Mersenne prime discovered » 2013-03-25 00:26:26

I do believe that they offer a 5000$ prize to the dicsoverer.

#1519 Re: Help Me ! » Stats » 2013-03-21 03:19:49

Since Σ(d - d)2 = 270, we get the sample mean difference.

#1520 Re: Introductions » Greetings from "digits" the dyscalculic savant » 2013-03-21 02:54:41

Welcome to the forum. Frankly I did not manage to read your inordinately long post though...

#1521 Help Me ! » Stats » 2013-03-21 02:51:50

ShivamS
Replies: 2

Twenty-two students were randomly selected from a population of 1000 students. The sampling method was simple random sampling. All of the students were given a standardized English test and a standardized math test. Test results are summarized below.

Student    English    Math    Difference, d    (d - d)2
1    95    90    5    16
2    89    85    4    9
3    76    73    3    4
4    92    90    2    1
5    91    90    1    0
6    53    53    0    1
7    67    68    -1    4
8    88    90    -2    9
9    75    78    -3    16
10    85    89    -4    25
11    90    95    -5    36
Student    English    Math    Difference, d    (d - d)2
12    85    83    2    1
13    87    83    4    9
14    85    83    2    1
15    85    82    3    4
16    68    65    3    4
17    81    79    2    1
18    84    83    1    0
19    71    60    11    100
20    46    47    -1    4
21    75    77    -2    9
22    80    83    -3    16
Σ(d - d)2 = 270
d = 1

What is the 90% confidence interval for the mean difference between student scores on the math and English tests? Assume that the mean differences are approximately normally distributed.

1+1.3

That is the answer I am getting, but am not sure.

#1522 Re: Jokes » Funny? » 2013-03-20 01:31:14

Poor statistician...

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