As shown in the figure, B and C divide the line ad into three parts: 2:4:5, M is the midpoint of AD, MC = 1, and find the length of CD

Let AB = 2K, then BC = 4K, CD = 5K
∴AD=11k
∵ m is the midpoint of AD
∴AM=5.5k
∵AC=2k+4k=6k
∴MC=0.5k=1
k=2
∴CD=5k=10

As shown in the figure, we know that ad = 5cm, B is the midpoint of AC, CD = 23ac

Let AC = x, have X + 23x = 5, the solution is: x = 3, that is, AC = 3cm, CD = 2, and B is the midpoint of AC, ab = BC = 32cm

As shown in the figure, we know that ad = 5cm, B is the midpoint of AC, CD = 23ac

Let AC = x, have X + 23x = 5, the solution is: x = 3, that is, AC = 3cm, CD = 2, and B is the midpoint of AC, ab = BC = 32cm

There are four. The first three are equal difference sequence, and the last three are equal ratio sequence. The sum of the first and the last two numbers is seven, and the sum of the middle two numbers is six

Let the four numbers be A-D, a, a + D, (a + D) ^ 2 / A
a-d+(a+d)^2/a=7
2a+d=6
The solution is d = 3 / 2 or - 2
A = 9 / 4 or 4
The four numbers are as follows
3/4,9/4,15/4,25/4
or
6,4,2,1

The sum of the three numbers in the equal ratio sequence is equal to 21. If the first number subtracts 1 and the third number subtracts 2, the equal difference sequence will be formed. Find the three numbers
RT

3,6,12.

It is known that the product of the first three terms of the increasing equal ratio sequence {an} is 512, and the three terms are subtracted by 1, 3 and 9 to form the equal difference sequence. The general term formula of the sequence {an} is obtained

Let the common ratio of the equal ratio sequence {an} be q, the product of the first three terms of the equal ratio sequence {an} be 512, a1a2a3 = a2q · A2 · a2q = (A2) 3 = 512, the solution is A2 = 8, then ∵ the three terms are subtracted from 1, 3, 9 to form the equal difference sequence, and ∵ A1-1, a2-3, a3-9 to form the equal difference sequence, then (A1-1) + (a3-9) = 2 (a2 -

In the four numbers, the first three numbers form an equal ratio sequence, and the last three numbers form an equal difference sequence. The sum of the first and last two numbers is 21, and the sum of the middle two numbers is 18

Let the second, third and fourth numbers be C-D, C, C + D respectively, then the first number is (C-D) & sup2. / C. according to the meaning of the title, C-D + C = 18 --- - (1) (C-D) & sup2 / / C + C + D = 21 --- - (2), the solution is C1 = 12, D1 = 6 or C2 = 6.75, D2 = - 4.75, so the four numbers obtained are: 3,6,12,18 or 18.75,11.25,6.75,2.25

There are three numbers in an equal ratio sequence, the sum of which is 21. If the third number subtracts 9, then they will be in an equal difference sequence. The three numbers are______ ．

Let three numbers be a, B, C. from the meaning of the question, we can see that a + B + C = 212B = a + (C − 9) B2 = AC. the solution is: B = 4, a = 1, C = 16 or B = 4, a = 16, C = 1. So the answer is: 16, 4, 1

Let a, B, C be an equal ratio sequence, the product of which is 8, and let a, B, C be an equal difference sequence by subtracting 1

It's obvious that a, B and C are 1, 2 and 4 respectively, which can be calculated

The product of three numbers is 8. If two times of the first number, three times of the second number and three times of the third number form an arithmetic sequence, we can find the three numbers

Let the first number be a, the second AQ and the third AQ ^ 2
a*aq*aq^2=8
3/2aq-2a=aq^2-3/2aq
We obtain a = 1q = 2
These three numbers are 1,2,4

As shown in the figure, B and C divide the line ad into three parts: 2:4:5, M is the midpoint of AD, MC = 1, and find the length of CD