Arc Subtend

This applet allows a learner to explore the relationship between the angle at the centre and angle on the circumference by the same arc. It also allows to explore that angle subtended by an arc on the circumference.

B

C

D

O

α = 3.0019663134302466 rad (slider from 0 to 6.283185307179586, step 0.017453292519943295)
O = (9.410833333333336, 0.8225)
c = Circle(O, 5.4)
B = Point(c)
C = Rotate(B, α, O)
k = CircleArc(O, C, B)
A = Point(c)
f = CircleArc(O, B, A)
a = Segment(O, A)
b = Segment(O, B)
D = Point(k)
d = Segment(D, A)
e = Segment(D, B)
δ = Angle(B, O, C)
g = Segment(D, C)
ε = Angle(B, D, C)
h = Segment(O, C)
E = (16.290833333333335, 6.1025)
text1_4: "" + α + ""
text1_5: "" + ε + ""
text2: "α = " + δ + ""