I'll do the first two problems to get you started
Problem 1
1/2 = 3/6
1/3 = 2/6
For the first fraction, I multiplied top and bottom by 3. Note how 3 is the denominator of the second fraction.
For the second fraction, I multiplied top and bottom by 2. Note how 2 is the denominator of the first fraction.
===============================================
Problem 2
1/2 = 5/10
3/5 = 6/10
Like with problem 1, I multiplied top and bottom of the first fraction by the value 5 which is the denominator of the second fraction. Likewise, I did the same for the second fraction using the first denominator. The steps are essentially the same, but the numbers are different.
Problem 3 will be handled the same way. I'll let you try it out.
4.5/3= 1.5*4
6 is your answer
When light moves from one medium to another, it is refracted. If it moves from a medium with refractive index n1 to one with refractive index n2, with an incidence angle to the surface normal of θ1, the refraction angle θ2 can be calculated from Snell's law.
The Snell's law states that the ratio of the sines of the angles of incidence and refraction of a wave (in this case beam/light) are constant when it passes between two given media.

Given that a <span>laser travels from glass to water at an angle of 35° with the normal, </span>

<span>. If water has an index of refraction of 1.33 and glass has an index of refraction of 1.52, then we have:
</span>

<span>
</span>
<span>the Slope would be (m) =<span>-6</span></span>
The answer is b
2cos x + 1 = 0
2 cos x = -1
cos x = -1/2
x = cos^1(-1/2)
(cos inverse (-1/2))
x = 120°