step 1 of 6
A full turn, all the way around back to where you started, is 360 degrees. Zoe watches a clock hand start at 12 and turn all the way around until it points at 12 again.
How many degrees is one full turn?
Degrees and turns
Know that angles are measured in degrees, where one degree is 1/360 of a full turn; understand that an angle turning through n one-degree angles has a measure of n degrees
What a learner can do afterwards
- Explain that a full turn is 360° and a right angle is 90°
- Describe what 'one degree' means in terms of a fraction of a circle
- State that an angle of 45° has turned through 45 one-degree angles
1 · Read
An angle is made from two rays that share one endpoint, the vertex. The meeting shows a turn. We measure turns in units called degrees. A full turn, all the way around back to where you started, is 360 degrees.
Try it together
Four equal quarter turns fill the full 360 degrees. Add them: 90 + 90 + 90 + 90 = 360. So each quarter turn is 90 degrees. A right angle is one quarter turn.
Tap to shade 1 of the 4 parts.
Try it together
A half turn is 180 degrees: 90 + 90. A three-quarter turn is 270 degrees: 90 + 90 + 90. A full turn is 360. A quarter turn is 90. A pointer turning clockwise from 12 to 9 for the first time, with no extra full turns, sweeps 270 degrees. The smaller opening between the final pointer direction and the fixed 12 direction is 90 degrees.
Tap to shade 3 of the 4 parts.
One degree is one tiny slice of a circle cut into 360 equal slices, so one degree is one 360th of a full turn. A single slice is a very small turn. Ninety slices side by side make a quarter turn. In this lesson we count whole one-degree slices to name whole-degree turns.
You can build whole-degree turns out of one-degree slices, like building a number out of ones. Twenty slices make a 20-degree turn. Sixty slices make a 60-degree turn. To name a turn in degrees, count how many one-degree slices fit inside it.
A right angle is a square corner, 90 degrees. An acute angle has a positive opening greater than 0 and smaller than 90 degrees. An obtuse angle is greater than 90 degrees and less than 180 degrees. A square has 4 corners, and every corner is a right angle.
A full turn is 360 degrees. One degree is one of 360 equal slices. Count whole one-degree slices to name whole-degree turns.
Ten fresh original tasks (x1-x10) and three fresh original readings (reading1, reading2, reading4) authored for this topic. One Khan Academy article retained and adapted: Angle basics review (academy:article:4th-engage-ny:x961121b324233fec). Two Khan Academy videos retained: Measuring angles in degrees (academy:video:4th-engage-ny:263439060) and Recognizing angles (academy:video:4th-engage-ny:x1781a3d6). All corpus licenses are null and unverified.
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3 · Play
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Where it sits
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
Then practise
34 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.