Answer:
A = pi 9/16 cm^2
Step-by-step explanation:
The circumference is 3/2 pi
The circumference is given by
C = 2 * pi *r
3/2 pi = 2 * pi *r
Divide each side by 2 *pi
3/2 pi / 2 pi = 2 pi r /2pi
3/4 cm = r
Now we can find the area
A = pi r^2
A = pi ( 3/4) ^2
A = pi 9/16 cm^2
It will equal 1/3 4/12= 1/3 1/3 is the answer
The value of 28 tens is basically doing 28 times 10(in case you didn't know). 28 times 10 is 280. So the value of 280 tens is 280.
I can't make out the summand in (d), and I addressed (c) in your other question.
(a)

We have for positive integers

that

. We also are aware that the series

converges, since it is a

-series with

. Since the

-series converges in absolute value, the alternating series must also converge by comparison.
- - -
(b)

By the alternating series test, this series will converge if the absolute value of the summand is increasing for some large enough

and approaches zero.
We have

for all

, and we also have that

(where we substituted

, so that

).
Therefore (b) also converges.