Answer:
21.4476105895
Step-by-step explanation:
Using a calculator 
A bird with roller blades.
Answer:
452.39 units^2
Step-by-step explanation:
formula: 
Answer:
The sum of the first 6 terms is 3,412.5.
Step-by-step explanation:
The second term of the geometric series is given by:

Where a1 is the first term and r is the common ratio. The seventh term can be written as a function of the second term as follows:
![a_{7}=a_{1}*r^{6} \\a_{7}=a_{2}*r^{5} \\10,240 = 10*r^{5}\\r=\sqrt[5]{1024} \\r = 4](https://tex.z-dn.net/?f=a_%7B7%7D%3Da_%7B1%7D%2Ar%5E%7B6%7D%20%5C%5Ca_%7B7%7D%3Da_%7B2%7D%2Ar%5E%7B5%7D%20%5C%5C10%2C240%20%3D%2010%2Ar%5E%7B5%7D%5C%5Cr%3D%5Csqrt%5B5%5D%7B1024%7D%20%5C%5Cr%20%3D%204)
The sum of "n" terms of a geometric series is given by:

The sum of the first 6 terms is 3,412.5.
Lateral surface area of a cylinder: 2πrh, r is the radius, h is the height.
area of the top and bottom circle: πr²
when h=2r, the total surface area is:
2πr(2r)+πr²+πr²=6πr²
the answer is 6πr²