# Unit 14 Section 1 : Coordinates

You will have used coordinates before. In this section, we revisit coordinates before starting work on lines and graphs.
Remember that the first number is the x-coordinate (right) and the second number is the y-coordinate (up).

The origin is the centre of the graph at ( 0 , 0 ).
If the x-coordinate is a negative number then the point will be to the left of the origin.
If the y-coordinate is a negative number then the point will be below the origin.

## Practice Question

Work out the answer to each of these questions then click on the button marked to see whether you are correct.

Look at the coordinate grid below.
 What are the coordinates of A? What are the coordinates of B? What are the coordinates of C? What are the coordinates of D?

## Exercises

Work out the answers to the questions below and fill in the boxes. Click on the button to find out whether you have answered correctly. If you are right then will appear and you should move on to the next question. If appears then your answer is wrong. Click on to clear your original answer and have another go. If you can't work out the right answer then click on to see the answer.

Question 1
Write down the coordinates of each of the points marked on the following axes:
 A ( , ) B ( , ) C ( , ) D ( , ) E ( , ) F ( , ) G ( , ) H ( , ) I ( , ) J ( , ) K ( , )
 NOTE: In the next few questions you need to plot points and draw lines on graphs. To plot a point, just click on the graph with your left mouse button. To draw a line, hold down the left mouse button at one end of the line and drag the pointer to the other end of the line. When you let go of the button the line will appear. If you make a mistake, press the delete key and the graph will be cleared.
Question 2
(a) Plot these points on the graph below and join them up with straight lines to form a triangle:
( 3 , –2 ) , ( –1 , 6 ) and ( –5 , –2 )

(b) What type of triangle have you drawn?

Question 3
(a) Plot these points on the graph below and join them up in order to form a shape:
( –1 , 4 ) , ( 2 , 5 ) , ( 5 , 4 ) and ( 2 , –1 )

(b) What is the name of the shape you have drawn?

 Question 4 The coordinates of 3 corners of a square are:                 ( 3 , 1 ), ( –1 , 1 ) and ( 3 , –3 ). What are the coordinates of the other corner? ( , ) You may find it helpful to use the graph on the right. Only the answer above will be marked. You need to upgrade your Flash PlayerGo to http://www.adobe.com/go/getflashplayer.

 Question 5 The coordinates of 3 corners of a rectangle are:                 ( –1 , 6 ), ( –4 , 6 ) and ( –4 , –5 ). What are the coordinates of the other corner? ( , ) You may find it helpful to use the graph on the right. Only the answer above will be marked. You need to upgrade your Flash PlayerGo to http://www.adobe.com/go/getflashplayer.
Question 6
A shape has corners at the points with coordinates:
( 3 , –2 ) , ( 6 , 2 ) , ( –2 , 2 ) and ( –5 , –2 ).

(a) Plot the points on the graph below and join them in order.

(b) What is the name of the shape?

Question 7
A shape has corners at the points with coordinates:
( 3 , 3 ) , ( 1, –1 ) , ( 3 , –5 ) and ( 5 , –1 ).

(a) Plot the points on the graph below and join them in order.

(b) What is the name of the shape?

Question 8
(a) Plot the coordinates below, joining them in order, to form a polygon:
( –5, 0 ) , ( –3 , 2 ) , ( –1 , 2 ) , ( 1 , 0 ),
( 1 , –2 ) , ( –1 , –4 ) , ( –3 , –4 ) and ( –5 , –2 ).