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Area moments — centroidal moment of inertia of a triangular section Find the second moment of area (area M.I.) of a triangle of base b and height h about an axis through its C.G. and parallel to the base. Choose the correct expression.

Difficulty: Medium

bh3/4
bh3/8
bh3/12
bh3/36

Correct Answer: bh3/36

Explanation:

ConceptThe centroidal area moment of inertia of a triangle about a horizontal axis through the centroid (parallel to the base) is a standard result.

ResultI_{G, ∥base} = \(\dfrac{b h^3}{36}\)

Why others are incorrectValues such as \(bh^3/12\) or \(bh^3/8\) correspond to different shapes/axes (e.g., rectangles) and are not applicable to a triangle about this specific centroidal axis.

Final Answerbh3/36

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