Find the area of the triangle whose vertices are A(2, −2), B(−3, 5) and C(−2, −4).

1. 1 · Write what is given and what is to be found Given: A(2, −2), B(−3, 5), C(−2, −4). To find: the area of triangle ABC.
2. 2 · Draw the figure Plot the three points roughly on the axes. Check that A → B → C goes anticlockwise.
3. 3 · Write the formula Area = (1/2){x₁(y₂ − y₃) + x₂(y₃ − y₁) + x₃(y₁ − y₂)}
4. 4 · Substitute the values = (1/2){2(5 − (−4)) + (−3)(−4 − (−2)) + (−2)(−2 − 5)}
5. 5 · Simplify step by step
   • 2 × 9 = 18
   • (−3) × (−2) = 6
   • (−2) × (−7) = 14
   • (1/2)(18 + 6 + 14) = (1/2)(38) = 19
6. 6 · Check and box the answer Area of triangle ABC = 19 sq. units. If time allows, recheck with the column method.

Scoring tip: Write every bracket with its sign. Most lost marks come from mistakes like − × −, not from the formula.