find the missing sum 3+9+15+....+87
677
just keep adding 6 until u get to 87
ohhh wait never mindd..my baadd lol
To find the missing sum in the sequence 3, 9, 15, ..., 87, we need to determine the pattern and then apply the appropriate formula to find the sum.
Looking at the numbers in the sequence, we can observe that each term is obtained by adding 6 to the previous term. Therefore, the common difference (d) between each term is 6.
Next, we can identify the first term (a) as 3.
Now, let's find out how many terms are in the sequence. We can do this by subtracting the first term from the last term and then dividing the result by the common difference. In this case, (87-3)/6 = 14. So there are 14 terms in the sequence.
To find the sum of an arithmetic sequence, we use the formula:
Sum = (n/2) * (2a + (n-1)d)
Where:
- n is the number of terms
- a is the first term
- d is the common difference
Now we can substitute the values into the formula:
Sum = (14/2) * (2*3 + (14-1)*6)
= 7 * (6 + 13*6)
= 7 * (6 + 78)
= 7 * 84
= 588
So, the missing sum in the sequence 3+9+15+....+87 is 588.