Circle Quiz

Area of original circle = πr²
New radius = 2r
Area of new circle = π(2r)² = 4πr² = 4 times original

The radius is the fixed distance from the center of the circle to any point on its boundary.

The circumference of a circle is given by C = πd, so the ratio of circumference to diameter is always π.

Two radii form a sector, which is a portion of the circle enclosed between them.

Concentric circles share the same center but have different radii.

Exactly two tangents can be drawn from an external point to a circle, touching it at two distinct points.

According to Thales' theorem, the angle subtended by a diameter at the circumference of a circle is always 90°.

For two circles to be externally tangent, the distance between their centers is equal to the sum of their radii.
Distance=r1 + r2 = 3 + 8 = 11 cm

A radius that is perpendicular to a chord always bisects the chord.

When a chord of a circle is equal in length to the radius, it forms an equilateral triangle with two radii.