how to increase the size of font awesome 4.7 icons in before class code example

Example 1: change font awesome icon size

<i class="fas fa-camera fa-xs"></i>
<i class="fas fa-camera fa-sm"></i>
<i class="fas fa-camera fa-lg"></i>
<i class="fas fa-camera fa-2x"></i>
<i class="fas fa-camera fa-3x"></i>
<i class="fas fa-camera fa-5x"></i>
<i class="fas fa-camera fa-7x"></i>
<i class="fas fa-camera fa-10x"></i>

Example 2: how to increase size of font awesome icon

#elementID {
    font-size:20px;
}