Coordinates and moving shapes · Usually met around P4
Plotting shapes
Missing corner: x from the one above or below, y from the one beside it.
How to do it
Method
Missing corner: x from the one above or below, y from the one beside it
A(1, 1), B(5, 1), C(5, 4) → D(1, 4)
Another way
Same steps
B → C is up 3, so A up 3 → D
In full
Plot the points in order on squared paper and join them with straight lines to make the shape. A rectangle's sides go straight across and straight up: corners above each other share x, corners side by side share y. A missing corner shares x with its neighbour above or below and y with its neighbour beside it. A square also has four equal sides: as many squares up as across. Or use “same steps”: however you get from one corner to the next, take the same steps from the opposite corner.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
Joining (1, 1), (4, 1), (4, 4) and (1, 4) in order makes a square.
True or false?
Show the answer and working
Answer: True
The side across is 4 − 1 = 3 squares, the side up 4 − 1 = 3: a square needs them equal.
Example 2
Each square on the paper is 1 cm wide. What is the perimeter of rectangle ABCD in cm?
Show the answer and working
Answer: 14 cm
AB = 4 − 1 = 3 cm and BC = 5 − 1 = 4 cm, so the perimeter is 2 × (3 + 4) = 14 cm.
Example 3
Square ABCD has A at (2, 3) and B at (3, 3), with C and D above AB. C is at (□, □).
Fill in each box
Show the answer and working
Answer: 3，4
AB is 3 − 2 = 1 squares; a square's sides are equal, so C is 1 straight above B: (3, 4).
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