The parts of a circle, and how chords and the centre are related. Equal chords, the perpendicular from the centre, and the angle that an arc makes at the centre and at the rim.
3 lessons, about 1 h 30 min3 simulations11 problems6 practice questionsPython in every lesson
Created by StemPy LabA circle has a centre, radii, chords, diameters and arcs. Equal chords of a circle make equal angles at the centre, and chords that make equal angles at the centre are equal. Both facts are proved from congruent triangles.
The perpendicular from the centre of a circle to a chord bisects the chord, and the line from the centre to the middle of a chord is perpendicular to it. Equal chords are equally far from the centre, and chords nearer the centre are longer.
The angle that an arc makes at the centre is double the angle it makes at any point of the remaining circle. So angles in the same segment are equal, and the angle in a semicircle is a right angle.
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