How is the area of the gable walls determined?

To determine the area of the gable walls, the correct approach involves understanding the geometry of a gable structure, which forms a triangular shape at the top of a wall. The area of a triangle is calculated using the formula: 1/2 multiplied by the base multiplied by the height.

In the context of gable walls, the base refers to the width of the wall at the bottom of the gable, and the height refers to the vertical height from the base to the peak of the triangle. Since there are typically two identical triangular gable walls on each side of a building, after calculating the area of one triangle, you should double it to determine the total surface area of both gable walls.

Thus, the area of the gable walls can be found using the formula of the triangle (1/2 * base * height) and then doubling the result, which aligns perfectly with the correct answer choice.