Since you are solving for diameter, and the equation is given to you, just isolate the variable for diameter (d).
(C)/π = (πd)/π
d = C/π is your formula you will use.
Plug in 56 for C
d = 56/π
d = ~17.825
~
Answer:
true, to my knowledge concentric circles are just circles that all have one main center.
Step-by-step explanation:
Given,
∠AOE = 30°
∠DOB = 40°
So, ∠EOD = 180 - (30+40) [angles on a straight line]
= 180 - 70
= 110
∠EOD = ∠COF [ vertically opposite angle]
∴ ∠COF = 110°
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.
