Question

find the centre of a circle using set squares

Answer 1

Use the set square to project two perpendicular lines from the points where the tangents touches the circle. Where the two line meet will be the centre of the circle.

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Draw line using 60-30 set square, on 60-degree side. ...

Draw the line BC, using 60-30 set square, on 30-degree side. ...

Join AC.

Let 'O' be the midpoint of AC.