Geometry · Foundation · 11 min
Inscribed angles
Move the observer around a circle. The angle can stay exactly the same.
WHAT HAPPENS IF…Will the angle change when P moves?
Preparing your experiment…
Draw radii from the center to A, B, and P. The resulting triangles are isosceles. Relating their base angles to the central angles gives an inscribed angle half the intercepted arc measure. In this construction the intercepted minor arc has measure 120°, while P stays on the other arc.
A detail that matters
P cannot coincide with either endpoint. Moving P onto the other arc changes the intercepted arc and gives 120° instead.
Keep the connection going
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