Lateral and Total Area of Pyramid and Cone

Applied Mathematics — Second Secondary

Common mistakes

Comparison aspect	Main idea	Keywords
Mistake	using the true height h instead of the slant height l in the lateral area rule. Correct: the lateral area uses the slant height which is the height of the lateral face	usingtrueheightinstead
Mistake	forgetting the area of the base when the total area is asked for. Correct: total area = lateral area + area of the base	forgettingareabasetotal
Mistake	multiplying the perimeter of the base by the slant height without dividing by 2. Correct: lateral area = ½ × perimeter × slant height	multiplyingperimeterbaseslant
Mistake	writing π r² for the lateral area of a cone. Correct: the lateral area is π r l π r² is the area of the circular base	writinglateralareacone

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