Why is the plane mirror inclined at `45^(@)` in a periscope ?

Explanation

To understand why the plane mirror in a periscope is inclined at 45 degrees, let's break down the explanation step by step.

### Step-by-Step Solution:

1. **Understanding the Periscope**:
A periscope is an optical device that allows an observer to see objects that are not in their direct line of sight. It typically consists of two mirrors and a tube.

2. **Role of the Mirrors**:
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