lesson
Updated 6 days ago · 1 view
Imagine you need to build a tiny bridge for an ant, and it has to be exactly the right size so it does not fall!
To draw straight paths of an exact length, we draw a line segment, which is a straight path with a clear start point and end point.
Look closely at a ruler: the numbered marks show centimeters, and the tiny tick marks between them are millimeters.
📊Interactive diagram
How do we make sure our line does not end up too long or too short before we even start drawing?
Starting at Zero
Always line up your pencil at the zero mark tick line, not at the plastic edge of the ruler.
Many rulers have a small blank gap before the zero mark, so starting at the edge makes your line too short.
📊Interactive diagram
What if your line needs to be longer than a whole centimeter, like 3 centimeters and 4 millimeters?
Step-by-Step Line Drawing
First, hold your ruler flat with your fingers spread like a spider so the ruler cannot slide.
Make a tiny dot at 0, slide your pencil along the edge past 3 centimeters, and then count 4 millimeter ticks past the 3.