SOLUTION: use the seuence of equations to find the unknown sum 1=1 1+3=4 1+3+5=9 1+3+5+....+1801=

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Question 881733: use the seuence of equations to find the unknown sum
1=1
1+3=4
1+3+5=9
1+3+5+....+1801=
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
S = ½(1 + 1801)n
S=1/2(1802)*n
S=901*n
An = A1 + (n - 1)d
1801= 1 + 2*(n - 1)
1800=2n-2
1798=2n
n=899
S = ½(1 + 1801)n
S=1/2(1802)*n
S=901*899=809,999