Question

The angle between 2 circles,each passing through the centre of the other is​

Answer 1

The angle between 2 circles,each passing through the centre of the other is​ 60°.

• Consider the attached figure while going through the following steps.
• Condition for circles to pass through the their centers is that, they should have same radius.
• OA = O'A = r = O'B = O'A
• ⇒ OC = O'C = r/2
• cos ∠ AO'B = O'C/AC = 1/2
• ⇒ ∠ AO'B = 120°
• ⇒ ∠ OAC = 120°/2 = 60°
• ∴ The angles between the circles is 60°