The common ratio of a geometric series is 1/4 and the sum of the first 4 terms is 170

what is the first term of the series? its 128

The first term is 128

Step-by-step explanation:please see attachment for explanation

128

Step-by-step explanation:

As common ratio is 1/4 ; let the first four terms of the geometric series be :

x , 1 / 4 .x , (1 / 4)2 .x , (1 / 4)3 .x  or

x , x / 4 , x / 16 and  x / 64

Now there sum is  170 , hence

x + x / 4 + x / 16 +  x / 64 = 170 or

(64a + 16a + 4a + a ) / 64  = 170 or

85a / 64 = 170

a = 128

Hence first first term of the series is

128

no not all of them.

step-by-step explanation:

some of them have a square base.

the arc length is found by finding the circumference of the full circle (2xpixradius) and then dividing by 4 to find just one quarter of the circle (90 degrees).