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Show that if two circles have the same radius, then their equal chords form equal angles at the centres.
 
circle session 1 question 4 image3.png
 
Given: Two Congruent Circles \(C_1\) and \(C_2\)
 
\(CD\) is the chord of \(C_1\) and
 
\(YZ\) is the chord of \(C_2\)
 
Also, \(CD =YZ \)
 
To Prove: Angle subtended by the Chords CD and YZ are equal
 
That is, \(∠COD = ∠YXZ\)
 
Proof:
 
In \(△COD\) and \(△YXZ\)
 
\(CO =\)
 ()
 
\(DO =\)
()
 
\( CD=\)
(Given)
 
\(△COD ⩭ △YXZ\)  ()
 
Therefore, \(∠COD = ∠YXZ\) ()
Answer variants:
\(YX\)
CZ
\(YZ\)
\(ZX\)