Final formula to solve each variable

Question

Assignment:

Question 1.

E = illumination
r = distance
I = intensity
Illumination:
Given the formula for E, show the final formula to solve for each of the following variables: E= I/4Πr²
r =
I =

Question 2.
n = index of refraction
v = speed of light in a substance
c = speed of light in a vacuum
Index of Refraction:
Given the formula for n, show the final formula to solve for each of the following variables: n= c/v
c =
v =

Question 3.
Mirrors:
Given the formula for 1/f, show the final formula to solve for each of the following variables: 1/d_{° +} 1/d_i = 1/f
do = object distance
di = image distance

Question 4.

Mirrors:
Given the formula for M, show the final formula to solve for each of the following variables: M = h_i/h_° =d_i/d_°
hi =
ho =
di =
do =