Find the sum of a geometric series of which a1=7, n=4 and r=3

280

Step-by-step explanation:

Use the formula: (a((r^n)-1))/(r-1)

= (7((3^4)-1))/(3-1)

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6

1/3 + 1/5 = 8/15.

step-by-step explanation:

hope it