# Homework Help: Optics mirrors problem with rearview of car

1. Jun 20, 2013

### alingy1

1. The problem statement, all variables and given/known data
I'm riding my car. My eye is 40cm from the rearview mirror. I want to know if I can see the car behind me. The car behind me is 2.5m large. Can I entirely see the car behind me in his whole wideness? The mirror is 23 cm long. The car is 4 meters behind us.

2. Relevant equations
Reflection laws.
Similar triangles.

3. The attempt at a solution
So, I drew this triangle (look attachment). And found that the eye, from where he his, can see the whole car. But, the question is not too clear. Do you think my steps are good?

#### Attached Files:

• ###### Photo pour Yu2.jpg
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2. Jun 20, 2013

### barryj

Where is the 4 meters measured from, the eye or the 23 cm mirror ? I think you have the correct answer though, at least app[roximately.

3. Jun 20, 2013

### barryj

Your diagram is confusing and not accurate. The triangles are not similar.
40/23 is not equal to 4/2.5