Conversion Graphs

a) since we are converting litres to pints, we need to locate the value 3 on the horizontal (x) axis and draw a line vertically upwards until it touches the black solid line of the graph.  Then we need to draw a line from this point horizontally to the left to find the corresponding value on the vertical (y) axis.  This value falls between 5.2 and 5.4 pints, so the approximate answer is

3 litres = 5.3 pints

 

b) since we are converting pints to litres, we need to locate 3.8 on the vertical (y) axis and draw a line horizontally to the right until it touches the blue line of the graph.  Then we need to draw a line from this point vertically down to find the corresponding value on the horizontal (x) axis.  This value falls between 2 and 2.2 litres. Since it is closer to 2.2 than 2, the approximate answer is

3.8 pints =2.15 litres

a) We know that 1 inch equals 2.54 cm, so we can plot the point (1, 2.54) on the graph.

 

If 1 inch equals 2.54 cm, then the cm equivalent of 3 inches can be calculated as follows:

3 \text{ inches} = 3 \times 2.54 \text{ cm} = 7.62 \text{ cm}

As a result, we can now plot the point (3, 7.62) on the graph.

 

If 1 inch equals 2.54 cm, then the cm equivalent of 6 inches can be calculated as follows:

6\text{ inches} = 6 \times 2.54 \text{ cm} = 15.24 \text{ cm}

As a result, we can now plot the point (6, 15.24) on the graph.

 

Now all we need to do is join the points, as per the graph below.

 

(We could have skipped one of the steps above as you only need to work out two points in order to draw a straight line, although 3 points does ensure that  you haven’t made an error.  If you have plotted 3 points and they are not in line, then one of your points has been calculated incorrectly.)

 

b) To use this graph to convert 10cm to inches, we must locate 10cm on the vertical (y) axis and draw a horizontal line to the right until it touches the line of the graph.  We then draw line vertically down to find the corresponding value on the horizontal (x) axis.  The value on the x-axis is halfway between 3.8 and 4, so

10 cm  \approx 3.9 inches

 

 

a)  For this first conversion, we are converting litres to pints.  Since pints is on the horizontal x axis, locate 4 on this axis and go up until you touch the line.  Then go across to the corresponding value on the vertical y axis.  We can see that this line touches  between 2.2 litres and 2.4 litres,  so we can say that

4 pints \approx 2.3 litres

 

b)  For the second conversion, we are converting pints to litres.  Since litres is on the vertical y axis, locate 5 on this axis and go across to the right until you touch the line.  Then go down to the corresponding value on the horizontal x axis.  We can see that this line touches  between 8.6 pints and 8.8 pints so we can say that

5 litres \approx 8.7 pints