Maths · Coordinate geometry. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
A point on a grid is fixed by two numbers called coordinates, written (x, y). The first number is the distance across from the origin: right is positive, left is negative. The second number is the distance up or down: up is positive, down is negative. The origin is the point (0, 0).
Every point on the x-axis has y = 0 and every point on the y-axis has x = 0.
Many questions join points to make a shape. Use what you know about the shape: opposite sides of a rectangle or parallelogram are equal and parallel, so the same movement across and up takes you along each of them.
Writing the coordinates in the wrong order, for example (2, −4) instead of (−4, 2). Remember "along the corridor, then up the stairs": x first, then y.
Answer: 10 square units
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