Answer:
A = 201 cm²
Step-by-step explanation:
We know that the area of a circle can be calculated with the formula:
A = πr² = π(d/2)²
with d being the diameter.
Therefore:
A = 3.14(8cm)² = 201 cm²
Answer:
atleast 385
Step-by-step explanation:
Given that an electrical power company is looking to expand into a new market. Before they commit to supplying the new area with electricity, they would like know the mean daily power usage for homes there.
Population std deviation = 
Sample size =
STd error of sample mean = 
Margin of error for 95% would be Critical value ( std error)
Here since population std dev is known we can use Z critical value= 1.96

Sample size should be atleast 385
100%-20%=80%
discount:250*20%=50
price of soft drinks:250*80%=200