I'm pretty sure the answer is 4 because, 4*21= 84.
80p=pr^2+p(2r)^2
80p=pr^2+4pr^2
80=r^2+4r^2
80=5r^2
16=r^2
r=4 for the smaller circle´s radius, and 8 is the larger circle´s radius.
Have a nice day, I hope this was helpful :D
Answer:
Option A
Step-by-step explanation:
The standard form of an equation of a circle is represented by the formula 
. Remember that 
is the center and 
is the radius squared.
So, the equation of the circle must be 
. Complete the square to change the form of the equations listed in the options and find the one that is equal.
Let's try this with option A. Move the constants to the right side, then use the completing the square method to place the equation in standard form:
The end result matches with the equation determined before, so option A is the answer.
Answer:
The investment at the end of the period will be $584.89.
Step-by-step explanation:
FV = PV e⁽ⁿˣ⁾
FV = Future Value = ?
PV = Present Value = $396
n = Interest Rate = 13%
x = time in years = 3
e = mathematical constant = 2.7183
FV = 396 x 2.7183⁽⁰°¹³ ˣ ³⁾
FV = 396 x 1.4770
FV = $584.89
