The first three numbers in a column are 1, 9 and 9, and each of them is the remainder obtained by dividing the sum of the three adjacent numbers in front of it by 3?

The first three numbers in a column are 1, 9 and 9, and each of them is the remainder obtained by dividing the sum of the three adjacent numbers in front of it by 3?

After looking at the law of the remainder of each number, the remainder obtained by dividing each number by 3 is the sum of the remainder obtained by dividing the three adjacent numbers in front of it by 3
1,0,0,1,0,0,1,0,0.
So 2002 = 3 * 667 + 1
So the second one is 1

For a column of numbers, the first three are 1, 9, and each of them is the remainder of the sum of the three adjacent numbers in front of it divided by 3. What is the number 1999 in this column?

（1999-3）÷13=153… 71999 is the seventh in the cycle section, which is 0. A: the number 1999 in this column is 0

In RT △ ABC, ab ┸ AC, ad ┸ BC are equal to D, AE is equal to ┸ bad, ask whether there are equal sides in the three sides of △ AEC? Explain the reason when AC = 1 / 2BC,
In RT △ ABC, ab ┸ AC, ad ┸ BC are equal to D, AE, and ┸ bad. Ask if there are equal sides in the three sides of △ AEC? Explain the reason
When AC = 1 / 2BC, does △ AEC have the same edge

(1) ∵ RT △ ABC and ad ⊥ BC
∴∠BAD ＋∠B =∠BAD ＋∠CAD =90°
∴∠B＝∠CAD
∵∠CEA=∠B+∠BAE
∴∠CEA＝∠CAD ＋∠BAE
And ∵ ∠ BAE = ∠ DAE
∴∠CEA=∠CAD＋∠DAE
That is, CEA = CAE
∴AC=EC
So there are equal sides in the three sides of △ AEC
(2) The reason is the same as (1) AC = EC
So △ AEC has equal sides
In RT △ ABC, AC = 1 / 2BC
∴∠B=30°,∠C=60°
The Δ AEC is an equilateral triangle

How much is 40 kg

40 tons 40000 grams

The school should add the same width (set as X meters) around a rectangular playground with a length of 100 meters and a width of 50 meters. Then how many square meters is the rectangular area after widening? When x = 2 meters, how many square meters is the rectangular area after widening

The area of the rectangle is (100 + x) (50 + x) square meters
When x = 2, the widened rectangular area is (100 + 2) (50 + 2) = 5304 square meters
The original rectangular area is 100x50 = 5000 square meters
5304-5000 = 304 square meters
The widened rectangular area increases by 304 square meters
Hope to help you, thank you!

The lengths of the three sides of a triangle are all integers, the perimeter is 11, and the length of one side is 4. What is the maximum possible length of the triangle? Explain the reason

The sum of the three integers is 11
4+6+1
4+5+2
4+4+3
The sum of two sides of a triangle is larger than the third, so 4 + 6 + 1 is excluded
So the maximum side length is 5

Xiao Ming runs from the first floor to the fifth floor in 20 seconds, and Xiao Fang's speed is half that of Xiao Ming. How long does it take Xiao Fang to run from the first floor to the fourth floor?

It takes 30 seconds for Xiao Fang to run from the first floor to the fourth floor

As shown in the figure, it is a triangle shaped pattern composed of several pots of flowers. Each side (including each vertex) has n (n > 1) pots of flowers, and the total number of pots of each pattern is s
According to this rule, what is the relationship between S and N? And when n = 19, the value of S is obtained
(1) o (2) o (3) o
o o o o o o
o o o o o o
o o o o

Unearthed Rongrong:
Let n be the number of rows (layers) of a triangular matrix
S is the number of flowerpots in the matrix,
S＝（1+n）n÷2
When n = 19
S＝（1+19）×19÷2＝190
Good luck and goodbye

Common plants (2) answers

What's the problem

Minimum value of algebraic formula √ (X & # 178; + 1) + √ [(4-x) &# 178; + 4] (0 ≤ x ≤ 4)

We can use the method of combination of number and shape, algebraic method, which is not easy to deal with. √ (X & # 178; + 1) + √ [(4-x) & # 178; + 4] = √ [(x-0) & # 178; + (0-1) & # 178;] + √ [(x-4) & # 178; + (0 + 2) & # 178;] the geometric meaning is the sum of distances from P (x, 0) to a (0,1) and B (4, - 2)