Math, asked by chaituP123, 1 year ago

b) Find the sum of 9 terms in the Arithmetic progression in which 5th term is 20.

Answers

Answered by samiksha83
5

t5=a+(n-1)d

20=a+4d...(1)

S9=9/2(2a+(n-1)d)

=4.5(2a+8d)

=4.5×40

=180

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