Area of Triangle — Standard Formula
The area of a triangle is half the product of a chosen base and its corresponding height.
Practice This ConceptMain explanation
Teacher explanation
Any side of a triangle can be treated as base, but the height must be perpendicular to that base. The formula works for right, acute, and obtuse triangles when the correct height is used.
Example
If base = 12 cm and height = 5 cm, area = 1/2 × 12 × 5 = 30 cm².
Simple analogy
Triangle area is half of the matching rectangle or parallelogram.
Common confusion
Students sometimes use a slant side as height even when it is not perpendicular to the base.
Exam tip
Look for the right-angle mark or perpendicular height before substituting values.
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