# Which number should come next? 144 ,121, 100, 81, 64 __?

By candyzone

@candyzone (63)

Malaysia

32 responses

@AJMSmith (112)

•

9 Feb 07

For a polynomial of order less than 5 49 is the only fit.
For an order 5 polynomial fit, ANY of the alternatives given could fit.
In fact a 5th order polynomial fit can be found for 144,121,100,81,64,u where u is any value you care to choose.
Consider this. A 5th order polynomial is of the form ax^5 + bx^4 + cx^3 + dx^2 + ex + f. 6 unknowns. a unique solution is a certainty for ANY value of u.

2 people like this

@sarawaken (360)

• Malaysia

10 Feb 07

Here I also have one question for you:
1,4,9,16,25,36,49.......what is the sum of the 100 terms of this number pattern?

1 person likes this

@livelifemax (91)

• India

22 Feb 07

Well lets look into this:
144-121=23
121-100=21
100-81=19
81-64=17
64-?=15
Definitely 49
There's an other simpler way
12^2=144
11^2=121
10^2=100
9^2=81
8^2=64
7^2=?
This way also its 49.

1 person likes this

@rezaahmed (81)

• Bangladesh

16 Feb 07

Well, as it is solved already What is the next problem?
But let me give you one puzzle.
Can you prove from 1=1 to 1=2

1 person likes this

@livinghell01 (398)

• Pakistan

13 Feb 07

It shoud be defintely 49 you took it this way:
144-121=23
121-100=21
100-81=19
81-64=17
and then the last number
64-(__)=15
that is
64-49=15
49 should be the perfect match for this problem continuing the series of odd numbers from 23-15

1 person likes this

@dareformore (794)

• Pakistan

12 Feb 07

Well The numbers are detecting By last-2. Or The Square Of the previous Number. So the next One Will be 49!!!

@sarawaken (360)

• Malaysia

10 Feb 07

is this a number sequences? my answer is 49 because 144 is perfect square of 12, 121 is perfect square of 11, 100 is perfect square of 10, 81 is perfect square of 9, 64 is perfect square of 64, so perfect square of 7 is 49. correct!!!!!

1 person likes this

@ryanbgico (258)

• Philippines

10 Feb 07

The correct answer is 49, and that's from the choices letter "d". Well it is an arithmetic progression with numbers having differences of also arithmetic progressing odd numbers starting 23, 21, 19, 17, and 15.
Well, you have made a unique discussion. I believe you are fond of mathematics. For me, its been a routine exercises when I studied Civil Engineering in my college years. Now that I am a Professional Civil Engineer already, its a great recall of those tricky math problems you have just posted.
You are definitely unique. Hear you around my friend.

1 person likes this