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The three sides of triangle are equal difference series, the circumference is 36, and the circumference of inscribed circle is 6 π Some people do that ∵ the three sides grow into an arithmetic sequence with a circumference of 36 Let the three sides be 12-n, 12, 12 + n respectively The circumference of the inscribed circle is 6 π --- radius of the inscribed circle r = 3 --- triangle area = (36 / 2) * 3 = 54 From Helen's formula: 54 & sup2; = 18 * 6 * (6 + n) * (6-n) --->27=36-n²--->n²=9--->n=3 --->The lengths of the three sides are 9, 12 and 15 respectively ∵ 9 & sup2; + 12 & sup2; = 15 & sup2;, ∵ the triangle is a right triangle Then why must one side be 12?
Three numbers are the arithmetic sequence, and the median is equal to three times
The length of three sides of a triangle is an arithmetic sequence, the circumference is 36, and the circumference of the inscribed circle is 6 π?
According to the circumference of 36 and equal difference, the middle term is: 12
According to the girth of inscribed circle 6N, the inscribed radius is 3
The triangle is an equilateral triangle with 12 sides
It is known that in the right triangle ABC, a, B and C are the opposite sides of a, B and C respectively
If a = 3, B = 4, then C =?
If a = 40, B = 9, then C =?
If a = 5, C = 13, then B =?
According to Pythagorean theorem, the first C is 5, the second is 41, and the third is 12
From {1,2,3 , 20} to make these three numbers into an arithmetic sequence. What is the maximum number of such a sequence
Determine the first and last two terms, because they must be the same odd or even
So take any 2 from 10 odd, (ordered) and any 2 from 10 even
So it's 2a10 2 = 180. Permutation number A10 2, understand?
Will 1, 2 If the nine numbers are divided into three groups averagely, the probability that the three numbers in each group can form an arithmetic sequence is ()
A. 156B. 170C. 1336D. 1420
The nine numbers are divided into three groups, including c39c36c33a33 group, in which the three numbers of each group are in arithmetic sequence, including {(1,2,3), (4,5,6), (7,8,9)}, {(1,2,3), (4,6,8), (5,7,9)}, {(1,3,5), (2,4,6), (7,8,9)}, {(1,4,7)}
Will 1, 2 If the nine numbers are divided into three groups averagely, the probability that the three numbers in each group can form an arithmetic sequence is ()
A. 156B. 170C. 1336D. 1420
The nine numbers are divided into three groups, including c39c36c33a33 group, in which the three numbers of each group are in arithmetic sequence, including {(1,2,3), (4,5,6), (7,8,9)}, {(1,2,3), (4,6,8), (5,7,9)}, {(1,3,5), (2,4,6), (7,8,9)}, {(1,4,7)}
Will 1, 2 If the nine numbers are divided into three groups averagely, the probability that the three numbers in each group can form an arithmetic sequence is ()
A. 156B. 170C. 1336D. 1420
The nine numbers are divided into three groups, including c39c36c33a33 group, in which the three numbers of each group are in arithmetic sequence, including {(1,2,3), (4,5,6), (7,8,9)}, {(1,2,3), (4,6,8), (5,7,9)}, {(1,3,5), (2,4,6), (7,8,9)}, {(1,4,7)}
Will 1, 2 If the nine numbers are divided into three groups averagely, the probability that the three numbers in each group can form an arithmetic sequence is ()
A. 156B. 170C. 1336D. 1420
The nine numbers are divided into three groups, including c39c36c33a33 group, in which the three numbers of each group are in arithmetic sequence, including {(1,2,3), (4,5,6), (7,8,9)}, {(1,2,3), (4,6,8), (5,7,9)}, {(1,3,5), (2,4,6), (7,8,9)}, {(1,4,7)}
What is the probability that the 9 numbers 1 to 9 can be divided into 3 groups equally
most urgent
The arithmetic sequence has the following conditions
(1,2,3)(4,5,6)(7,8,9)
(1,2,3)(4,6,8)(5,7,9)
(1,3,5)(2,4,6)(7,8,9)
(1,4,7)(2,5,8)(3,6,9)
(1,5,9)(2,3,4)(6,7,8)
Then nine numbers were divided into three groups with 280 cases
5 / 280 = 1 / 56
Take any three different numbers from the 20 numbers 1-20 to form the arithmetic sequence. How many such different arithmetic sequences are there? Please explain the reasons in detail
a. If B and C are equal difference sequence, then B = (a + C) / 2
Therefore, any two numbers a and C with the same odd or even number have b = (a + C) / 2, so that a, B and C are arithmetic sequence,
There are 45 ways to choose the same odd
There are 45 ways to choose the same pair
So there are 90 kinds of arithmetic sequence
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