Monday
Monday: Angles and degrees
Ferris the Fox unfolds his trail map at a fork in the path.
"Our trail turns here," he says, tracing the paths with his paw. "But how much does it turn?"
Bennie the Bear lays two long sticks on the ground so their ends touch.
"Two rays that start at the same point make an angle," Bennie explains.
Ferris opens the sticks wider, then closer. "The angle changes as the sticks turn!"
"We measure that turn in degrees," says Bennie. "A full turn all the way around is 360 degrees."
Ferris grins and adjusts his green backpack. "Then let us learn our turns."
Learn it: angles are turns
A ray starts at one point and goes on and on in one direction.
An angle is two rays that share an endpoint. The shared point is the vertex.
We measure angles in degrees. A full turn around a circle is 360 degrees.
One degree is 1/360 of a full turn.
A quarter turn is 360 ÷ 4 = 90 degrees. That is a right angle.
An acute angle is less than 90 degrees.
An obtuse angle is more than 90 degrees but less than 180 degrees.
A straight angle is a half turn, 180 degrees.
- Read the question.
- Tap your answer.
What kind of angle is this?What kind of angle is this?
What kind of angle is this?What kind of angle is this?
What kind of angle is this?- Read the question.
- Tap your answer.
- Read the question.
- Tap your answer.
What kind of angle do the clock hands make?
What kind of angle do the clock hands make?
What kind of angle do the clock hands make?- Think about how far each angle turns.
- Tap them from smallest to largest.
| Sentence | True or false? |
|---|---|
| A right angle measures 90 degrees. | ? |
| A full turn is 180 degrees. | ? |
| An obtuse angle is less than 90 degrees. | ? |
| 360 ÷ 4 = 90 | ? |
Make a quarter turn to your right. You turned 90 degrees.
Make a half turn. You turned 180 degrees.
Find 3 right angles at home, like the corner of a book.
Great turning! Tomorrow we measure and add angles.