Start at the right
The starting ray points right and positive sweeps move counterclockwise.
Angle Explorer
Sweep a ray around a dial and compare angle size with quarter turns and complete rotations.
Grades 3–5 · Geometry
Your goal
Sweep the blue ray counterclockwise through 90 degrees. Count complete turns as well as the final ray direction.
Reduced motion is on. The controls still update the scene.
0 degrees is 0 complete turns and 0 degrees more. 0 quarter turns in all.
degrees
This dial measures rotations in 15 degree steps up to two full turns. A matching final ray is only part of the goal. The accumulated sweep must also match.
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Learn with Angle Explorer
Angle Explorer helps upper elementary students connect angle measurement with movement around a circle. Children sweep a blue ray counterclockwise in 15 degree steps or add a complete quarter turn with one button. The dial shows its current direction, and separate counters retain every full rotation. Goals progress from familiar right angles to sweeps greater than one full turn. Students discover why rays at 90 degrees and 450 degrees point in the same direction even though the total angles traveled are different.
What to look for
Count quarter turns
A quarter turn is 90 degrees and four quarter turns make one full turn.
Keep counting
A full turn returns to the starting direction while adding 360 degrees.
For teachers and curious learners
Measure accumulated rotations and distinguish full turns from final ray direction. Ask students to predict what will happen, change one setting, and explain what they observe. Learn gives a starting point. Practice and Challenge offer new goals with the same scene.
The dial accumulates angles in 15 degree steps between 0 and 720 degrees. A gold ray shows the target direction, but success also requires the correct accumulated sweep. Updates are static and user controlled.