Hope this helps....am I close

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Balmer examined the four visible lines in the spectrum of the hydrogen atom; their wavelengths are 410 nm, 434 nm, 486 nm, and 656 nm. He played around with these numbers and eventually figured out that all four wavelengths (symbolized by the Greek letter lambda) fit into the equation
The number n is just an integer; the above formula gives the longest wavelength, 656 nm, when n=3, and gives each of the shorter wavelengths as n increases up to 6.
diameter = 2 x radius of circle
Circumference of Circle = PI x diameter = 2 PI x radius
where PI = = 3.141592...
Area of Circle:
area = PI r2
Length of a Circular Arc: (with central angle )
if the angle is in degrees, then length = x (PI/180) x r
if the angle is in radians, then length = r x
Area of Circle Sector: (with central angle )
if the angle is in degrees, then area = (/360) PI r2
if the angle is in radians, then area = (/2) r2
Equation of Circle: (cartesian coordinates)
for a circle with center (j, k) and radius (r):
(x-j)2 + (y-k)2 = r2
Equation of Circle: (polar coordinates)
for a circle with center (0, 0): r() = radius
for a circle with center with polar coordinates: (c, ) and radius a:
r2 - 2cr cos( - ) + c2 = a2
Equation of a Circle: (parametric coordinates)
for a circle with origin (j, k) and radius r:
x(t) = r cos(t) + j y(t) = r sin(t) + k
