Answer:
It is stratified random sampling.
Step-by-step explanation:
Stratified random sampling is a method of sampling that involves the division of a population into smaller sub-groups known as <em>strata.</em>
The strata are formed based on members' shared attributes or characteristics, in this case their race.
Stratified random sampling is also called <em>proportional random sampling</em> or <em>quota random sampling</em>
an = a1r^(n-1)
a5 = a1 r^(5-1)
-6 =a1 r^4
a2 = a1 r^(2-1)
-48 = a1 r
divide
-6 =a1 r^4
---------------- yields 1/8 = r^3 take the cube root or each side
-48 = a1 r 1/2 = r
an = a1r^(n-1)
an = a1 (1/2)^ (n-1)
-48 = a1 (1/2) ^1
divide by 1/2
-96 = a1
an = -96 (1/2)^ (n-1)
the sum
Sn = a1[(r^n - 1/(r - 1)]
S18 = -96 [( (1/2) ^17 -1/ (1/2 -1)]
=-96 [ (1/2) ^ 17 -1 /-1/2]
= 192 * [-131071/131072]
approximately -192
Answer:
62,500 pi
Step-by-step explanation:
diameter = radius + radius
d = 2r
r = d/2
A = 4pi r^2
= 4 pi (d/2)^2
= 4pi d^2/4
= 4pi* 250^2/4
= 4pi * 62,500/4
= 4pi * 15625
= 62,500 pi
By the law of cosines, the angle

satisfies

which reduces to

which converts to approximately 77 degrees (this can be done my multiplying by 180 and dividing by pi).