T = 2 π / | 4/7 |
T = 2 π / 4/7
T = 2 π × 7 / 4
T = 7 π / 2
Thus the correct answer is option A .
Answer:

Step-by-step explanation:
In order to write the series using the summation notation, first we need to find the nth term of the sequence formed. The sequence generated by the series is an arithmetic sequence as shown;
4, 8, 12, 16, 20...80
The nth term of an arithmetic sequence is expressed as Tn = a +(n-1)d
a is the first term = 4
d is the common difference = 21-8 = 8-4 = 4
n is the number of terms
On substituting, Tn = 4+(n-1)4
Tn = 4+4n-4
Tn = 4n
The nth term of the series is 4n.
Since the last term is 80, L = 4n
80 = 4n
n = 80/4
n = 20
This shows that the total number of terms in the sequence is 20
According to the series given 4 + 8 + 12 + 16 + 20+ . . . + 80
, we are to take the sum of the first 20terms of the sequence. Using summation notation;
4 + 8 + 12 + 16 + 20+ . . . + 80 = 
We have an equation: 56/? = 4/100
Cross multiply:
4*? = 56*100
⇒ ? = 56*100/4
⇒ ?= 1,400
4% of 1,400 days is 56 days~
There are some area calculators on google if you need but I will try work it out..... if I don’t know I won’t send another answer
Answer:

Step-by-step explanation:
- Height of cone (h) = 7 cm
- Formula for Volume of cone is given as:
- Plugging the values of h and r in the above formula, we find: