Using the pattern above as an aid, evaluate the sum:
1 + 2 + 3 + 4 + 5 + 4 + 3 + 2 + 1
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25
1^2=1 ; 2^2=4; 3^3= 9 ; 4^2= 16 ; 5^2 = 25; so 25 is the answer
5+(4+1)+(4+1)+(2+3)+(2+3)=25
good
Ridiculously easy.
25
1+2+3+4+5+4+3+2+1=25
25
1+2+3+4+5+4+3+2+1=5+2(1+2+3+4) 5+2(10)=25
25
25
Ans is 25
25
always mid term square here 5 so 5 square is equal to 25
if we see , the sequence is 1^2,2^2,3^2,4^2,5^2.Therefore, 1,4,9,16 ,25.
It's easy...............
r u sure 5^5=25 or 3125
25
Here is a seris...
1^2=1
2^2=4
3^2=9
4^2=16
5^2=25
If we are on term four, then the number is just h^2 = 16. So the next term is h^2 + 2h + 1, or (h + 1)^2 = 25
Square the no.of Items in the Center of the Pyramid.
1+2+1= 2^{2}=4 1+2+3+2+1=3^{2}=9 1+2+3+4+3+2+1=4^{2}=16 there fore, 1+2+3+4+5+4+3+2+1=5^{2}=25
1+2+3+4+5+4+3+2+1 = (1+4)+(2+3)+(5)+(4+1)+(3+2) = 5+5+5+5+ 5 = 5*5 = 25
ans can be find out by the maximum value in the question and just square it . in our question max. value is 5 after squaring it .we get 25 as our answer alternatively just add those values given in the question as 1+2+3+4+5+4+3+2+1=25.
look at the number exactly at the middle of patterns. (easiest,fastest way to think)
1+2+3+4+5+4+3+2+1
5 is the exactly middle number.
Now, just square it. 5^2
you get the answer 25.
Applying formula NXN that is maximum number is 5X5 =25 Ans K.K.GARG.India
if the middle term is n then use ( ) n times and add two in every term as ( 1)+(1+2)+(1+2+2)+(1+2+2+2)+(1+2+2+2+2) no of 2 in nth term will be (n-1) answer is 25
terribly easy...should have been a challenge!
Just add the numbers up! 2(1+2+3+4)+5=25
n(n+1)/2+(n-1)n/2 = (n^2+n+n^2-n)/2 = n^2, here n=5 so result is 25
nice
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Refer to the solution of this problem which suggests that 1 + 2 + 3 + . . + ( n − 1 ) + n + ( n − 1 ) + . . . + 3 + 2 + 1 = n 2 .
Using that we can say ----->
1 + 2 + 3 + 4 + 5 + 4 + 3 + 2 + 1 = 5 2 = 2 5