Measuring With a Ruler

Before we start this topic online, it is important to note that everything that is 'measured' on the screen is not drawn to scale. That means that even if you print the page, the measurements shown may not be accurate. These pages are here to show you how to work your ruler - for practice refer to the examples and practice questions in your booklet.

Reading Your METRIC Ruler

Below is shown a section of a sample ruler with metric measurements. The numbers (and large tickmarks) on the ruler represent centimeters and the little tick marks represent millimeters. It is important to remember that a millimeter is 1/10 of a centimeter, or 0.1 of a centimeter. This means that each tick you move along the ruler adds .1 to the measurement. The very left hand side of the ruler is 0 centimeters. The animation shows each measurement (the reading off the ruler) from 0 to 3 centimeters. Note that the numbers you see are all in centimeters. (ie. If you see 2.6, that means 2.6 cm.)

This ruler is not drawn to scale - each centimeter shown is much larger than in real life.

Example

Measure the length of the following line in centimetres:

Solution

YOU CAN'T ACTUALLY MEASURE THIS LINE THAT IS SHOWN ON THE SCREEN! This is just an example to show you how you would work your ruler. These pictures are NOT TO SCALE. That being said, the way you would go about doing this question is to lay your ruler down with the 0 mark at the left end of the line, and read where the line ends on the ruler. This is pictured below:

Since the line ends at the fourth 'tic' past the 3 on the ruler, the line is 3.4 cm long.

Reading Your IMPERIAL Ruler

Below is shown a section of a sample ruler with imperial measurements (inches). The numbers (and large tickmarks) on the ruler represent inches and the little tick marks represent one sixteenth (1/16) of an inch. You can tell they are 1/16, as there are 16 little tick marks making up each inch. This means that each tick you move along the ruler adds 1/16 to the measurement. This can make imperial measurement more difficult than metric, as you have to use fractions! The very left hand side of the ruler is 0 centimeters. The animation shows each measurement (the reading off the ruler) from 0 to 2 inches. Note that the numbers you see are all in inches. (ie. If you see 1 113/16, that means 1 13/16 inches.)

Again, this ruler is NOT to scale! Real inches are smaller than what is shown here.

Example

Measure the length of the following line in inches:

Solution

Remember: This is NOT TO SCALE. This is just a DEMONSTRATION of how to USE your ruler. Put your ruler by the line with the left edge at the 0 mark of your ruler. Then read which mark the line reaches off the right of your ruler. Remember, different from centimeters, each tick on your inch ruler is 1/16 of an inch. This will look like:

As you can see, the line stops at the 13th tic mark past the 1. That makes this measurement 1 13/16".

It is hard to make sample questions for this topic, as the scale is impossible to set. There are good examples (and questions) in your booklet - look there for some practice. You can now head back to the Design and Measurement main page.