Area of triangle using coordinates
This concept finds the area of a triangle directly from the coordinates of its vertices.
Practice This ConceptMain explanation
Teacher explanation
When base and height are not easy to see, the coordinate area formula gives a reliable answer. It uses the coordinates in a fixed order and produces area without drawing measurements by hand. The absolute value is important because area must always be non-negative.
Example
For vertices (1, 1), (5, 1), and (1, 4), the base is 4 units and the height is 3 units, so the area is 6 square units.
Simple analogy
Triangle area from coordinates still follows half of base times height.
Common confusion
Students often forget the half factor or the absolute value, which gives an incorrect area.
Exam tip
Write the vertices carefully and keep the order consistent. If the final value is negative, take its absolute value before dividing by 2.
Answer writing and exam use
1-mark use
Write the exact meaning of area of triangle using coordinates in one clean line.
2-mark use
Define area of triangle using coordinates and add one example or condition.
3-mark use
Explain area of triangle using coordinates, show the method or example, and mention the common mistake.
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