Answer:
8 π .
Step-by-step explanation:
radius increases at a constant rate of 1 in/sec.
dr / dt = 1
where r is radius .
radius after 4 sec
r = 1 x 4 = 4 in
area A = π r²
differentiating both sides
dA / dt = 2 π r dr / dt
Putting dr / dt = 1 , r = 4 in
dA / dt = 2 π x 4 x 1
= 8 π sq in per sec.
Area increases at the rate of 8 π per sec.
Answer:
-51.4
Step-by-step explanation:
The ratio can be determined as,

Thus, the requried ratio is 7:12.
Answer:
0.55 mile / minute
Step-by-step explanation:
The average change of altitude per minute would simply be the ratio of distance descended over time. That is:
average change of altitude = distance / time
average change of altitude = 0.44 mile / 0.8 minutes
average change of altitude = 0.55 mile / minute
Answer:
Since a blogger has 400 subscribers to her blog in January, and the number of subscribers has grown by a factor of 1.5 every month since the, to write a sequence to represent the number of subscribers in the 3 months that followed, the following reasoning has to be made:
January: 400 subscribers
February: 400 x 1.5 = 600 subscribers
March: 600 x 1.5 = 900 subscribers
April: 900 x 1.5 = 1,350 subscribers