Circles in Mathematics

What is the formula to find the circumference of a circle?

• 3.14r

• r^2

• 2πr

• 4r

If the radius of a circle is 5 cm, what is its diameter?

• 3 cm

• 10 cm

• 15 cm

• 7 cm

What is the relationship between the radius and the diameter of a circle?

• The radius and diameter are equal in length.

• The diameter is half the length of the radius.

• The diameter is twice the length of the radius.

• The radius is twice the length of the diameter.

What is the formula to find the area of a circle?

• πr^2

• r/2

• π/r

• 2πr

If the diameter of a circle is 12 cm, what is its radius?

• 10 cm

• 6 cm

• 15 cm

• 3 cm

What is the value of pi (π) in the context of circles?

• 3.14159

• 4.6692

• 2.71828

• 5.6789

What is the formula to find the area of a sector of a circle?

• A = 2πr

• A = πr^2

• A = (θ/180) * π * r^2

• A = (θ/360) * π * r^2

If the circumference of a circle is 36π cm, what is its radius?

• 12 cm

• 24 cm

• 30 cm

• 18 cm

What is the relationship between the radius and the area of a circle?

• The area of a circle is πr^2, where r is the radius.

• The area of a circle is 3r^2, where r is the radius.

• The area of a circle is 0.5πr^2, where r is the radius.

• The area of a circle is 2πr, where r is the radius.

If the area of a circle is 64π cm², what is its radius?

• 8

• 12

• 16

• 4