Step 1: The formula for calculating the sum of interior angles of a polygon is:
\[
\text{Sum of interior angles} = (n - 2) \times 180^\circ
\]
Step 2: Calculating for a triangle (\( n = 3 \)):
\[
(3 - 2) \times 180^\circ = 180^\circ
\]
Step 3: Calculating for a quadrilateral (\( n = 4 \)):
\[
(4 - 2) \times 180^\circ = 360^\circ
\]
Step 4: Increase in the sum of interior angles when the number of sides increases from 3 to 4:
\[
360^\circ - 180^\circ = 180^\circ
\]
Conclusion: The sum of interior angles increases by \( 180^\circ \), hence the correct answer is option (B).