Answer:
He should do 30 strips
Step-by-step explanation:60 times 3 is180 so and aa 0 to 180 and get 1800 so then you and the 0 to 3 and get 30
Answer:
10.2π
Step-by-step explanation:
Given data
Area of circle= 81 ft^2
Also, the expression for the area of a circle is
A=πr^2
substitute
81=3.142*r^2
r^2= 81/3.142
r^2= 25.77
square both sides
r= √25.77
r= 5.1
Also, the expression for the circumference is
C= 2πr
substitute
C= 2*π*5.1
C= 10.2π
Hence the circumference is 10.2π
The Jacobian for this transformation is

with determinant
, hence the area element becomes

Then the integral becomes

where
is the unit circle,

so that

Now you could evaluate the integral as-is, but it's really much easier to do if we convert to polar coordinates.

Then
