An angle marking is like a meter stick marking. The marking of 1.2m on a meter stick only means an object is 1.2m long if the object starts at zero meters. If it starts at 0.2 meters then the object is really 1.0 meters long. You will be making angle calculations from angle markings in a similar fashion.

Given a green marking of 223 degrees and a straight-on marking of 253 degrees, how much has the light bent?

The angle of bend = 20°

Explanation:

Since the question describes that the angle marking is similar to the metre stick marking.

The length of the object when it begins at 0 meters on the meter rule

= 1.2 m

The length of the meter stick when it begins at 0.2 m on the meter rule

= 1.0 m

The difference in length of the object based on the markings

= 1.2 - 1.0 = 0.2 m

If the green marking is on 223°, i.e. θ₂ = 223°

and the straight marking is on 253°, i.e.  θ₁ = 253°

The angle of bend =  θ₁ -  θ₂

The angle of bend = 253° - 223°

The angle of bend = 20°