Idea 1of 24
An angle is a turn
What makes one angle bigger than another?
Today you'll discover
- what an angle is made of
- why long arms do not make a big angle
- how to see which angle opens wider
Think firstTwo angles, P and Q
Which angle is bigger, P or Q?
Decide first, then press Next. Look at the opening between the arms, not their length.
Two angles side by side. P on the left has long arms that open only a little; Q on the right has short arms that open wider. Curves then mark each opening. Next, two angles that open the same amount, one with long arms and one with short, and a dashed copy of the first laid exactly on the second. The last step shows P with short arms opening wide and Q with long arms opening less.
See the whole ideathe big idea and the key word, in one place
The big idea
An angle is the turn between two arms that meet at a vertex; arm length does not matter.
Easy to get wrongDo not judge an angle by how long its arms are or how big the drawing is. A tiny drawing can hold a wide angle.
Angles around youThe hands of a clock, an open door and a slice of pizza each make an angle at the point where two edges meet.
Key words
- angle
- the turn between two arms that meet at a point
- vertex
- the point where the two arms of an angle meet
- arm
- one of the two straight lines that make an angle
Ready to use it?
- Compare two angles with different arm lengths.
- Point to the vertex and the arms of an angle.