Unpolarized light is passed through three successive Polaroid filters, each with its transmission axis at 45.0° to the preceding filter. What percentage of light gets through?

The percentage is  

Explanation:

From the question we are told that

    The  axis is is  at  

Generally the of intensity light emerging from the first polarizer is mathematically represented as

Where   is the intensity of unpolarized light

       Now the light emerging from the second polarizer is mathematically represented as

  Now the light emerging from the third  polarizer is mathematically represented as      

Now the percentage of the intensity of light that emerged with respect to the intensity of  the unpolarized light is

a. spokes of a wheel.

as indicated in the question radial contains rad, also found in radius, so the fracture's would span the radius.