Basic Geometric Ideas: Circles

How many radii are shown in the circle?

• 1

• 3

• 4

• 5

Answer explanation

There are 5 radii in this figure.

Radii AB, BC, BE, BF, and BH

In this geometric figure, it is called _____.

• Circle A

• Circle B

• Circle C

• Circle E

The following are arcs in the circle except:

• Arc AD

• Arc BF

• Arc GH

• Arc FC

Answer explanation

An arc is the part of a circle determined by two points and all points between them.

BF is not actually an arc but rather a radius. The rest of the choices in this question are Arcs.

How many chords are shown in the circle?

• 2

• 1

• 4

• 3

Answer explanation

There are 4 chords in this figure.

Chords DH, FG, AC, and HF.

AC and HF are considered a chord even it passes through the center.

A chord is a line segment connecting two points on the circle.

How many diameter is in the circle?

• 1

• 2

• 4

• 5

Answer explanation

There are 2 diameters in this figure. Chord AC and Chord FH passes through point B.

What is the radius in this figure?

• 10

• 1

• 5

• 20

What is the diameter in this figure?

• 2 cm

• 4 cm

• 8 cm

• 16 cm

What is the circumference of this figure?

• 10 cm

• 15.7 cm

• 31.4 cm

• 62.8 cm

What is the circumference of this figure?

• 3 m

• 9 m²

• 18.84 cm

• 9.42 m

What is the area of the circle?

• 20 cm

• 62.8 cm

• 100 cm²

• 314 cm²