Given:
The sum of two terms of GP is 6 and that of first four terms is 
To find:
The sum of first six terms.
Solution:
We have,


Sum of first n terms of a GP is
...(i)
Putting n=2, we get


...(ii)
Putting n=4, we get



(Using (ii))
Divide both sides by 6.
Taking square root on both sides, we get

Case 1: If r is positive, then using (ii) we get
The sum of first 6 terms is




Case 2: If r is negative, then using (ii) we get
The sum of first 6 terms is




Therefore, the sum of the first six terms is 7.875.
Answer:
?
Step-by-step explanation:
Think of it this way: Lets add numbers in pairs, starting at the very outer 2 numbers (19 and 77) then go in by one and add the second number and the second to last (20 and 76), then (21 and 75) and so on. The sum of all of these pairs are all the same: 96. How many 96s will we have? Well since we're coming from each end toward the middle adding pairs we will have half the distance between 19 and 77, that is (77-19)/2 = 29. So we can actually just take 96*29 = 2784. This is the sum of all numbers between 19 and 77
Answer:
X equals 6°.
Step-by-step explanation:
There is a geometry rule that states the outer angle of a triangle's interior angle is equivalent to the sum of the remaining two interior angles of the triangle. Following this rule, you can get that (6x + 8) + (5x + 8) = 82° ⇒ 11x + 16 = 82° ⇒ 11x = 66° ⇒ x = 6°.