18. The perimeter is simply √3 + √3 + √3 + √3 or 4√3cm, since the perimeter is just all sides added together. You could add the decimal numbers together using a calculator, which I'm not sure if you're supposed to do in your class.
The area is just width times length, so √3 • √3 = 3cm².
19. The perimeter is 2√5 + 2(9 - √5).
This can also be written as 2√5 + 18 - 2√5, which leaves you with a perimeter of 18ft.
The area would be √5 • (9 - √5), which leaves you with (9√5 - 5)ft².
20. The formula for the perimeter (or circumference) of a circle is π times the diameter of the circle. Using the radius of the circle, 1/π, the diameter is 2/π, so
π • 2/π = 2. The circumference of the circle is 2 inches.
The area of the circle is calculated with the equation πr², so
π(1/π)² = π • 1/(π²) = π/(π²) = π. The area is simply π in².
Answer: dr/dt = 9/(24pi) cm per minute
9/(24pi) is approximately equal to 0.119366
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Work Shown:
Given info
dS/dt = 18 cm^2/min is the rate of change of the surface area
r = 6 cm is the radius, from the fact that the diameter is 12 cm
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Use the surface area equation given, apply the derivative, plug in the given values and then isolate dr/dt which represents the rate of change for the radius
S = 4*pi*r^2
dS/dt = 2*4*pi*r*dr/dt
dS/dt = 8*pi*r*dr/dt
18 = 8*pi*6*dr/dt
18 = 48*pi*dr/dt
48pi*dr/dt = 18
dr/dt = 18/(48pi)
dr/dt = (9*2)/(24*2pi)
dr/dt = 9/(24pi)
The units are cm per minute, which can be written as cm/min.
Answer:
Riding 2 miles = $6.50
Riding m miles: C = 1.25m + 4
Step-by-step explanation:
(1.25)*(2) + 4 = $6.50
X= 0, 1/2
Solve : 9x • (2x-1)•(4x^2+2x+1)
