What is the measure of each interior angle of a regular polygon with 8 sides?

Step 1: Use formula

Each interior angle = $\frac{(n-2)\times 180^\circ}{n}$

Step 2: Substitute $n = 8$

$\frac{(8-2)\times 180}{8} = \frac{6 \times 180}{8}$

$= \frac{1080}{8} = 135^\circ$

Final Answer: 135°