Exploring Circumference and Area of Circles

What is the formula for the circumference of a circle using its radius?

• A = πd^2

• A = πr^2

• C = πd

• C = 2πr

If a circle has a diameter of 37 inches, what is its approximate circumference?

• 58.09 inches

• 37π inches

• 74.14 inches

• 116.18 inches

Given a circle with a radius of 12 cm, what is its circumference?

• 24π cm

• 48π cm

• 37.68 cm

• 75.36 cm

What is the radius of a circle if its area is 25π square meters?

• 12.5 meters

• 5 meters

• 25 meters

• 10 meters

How do you calculate the area of a circle?

• A = πd

• A = πd^2

• A = 2πr

• A = πr^2

If the diameter of a circle is 14 inches, what is its area?

• 49π square inches

• 153.86 square inches

• 28π square inches

• 196π square inches

Using the Pythagorean theorem, what is the diameter of a circle if one side of the right triangle inside it is 16 units and the other is 30 units?

• 22 units

• 15 units

• 46 units

• 34 units

What is the circumference of a circle with a diameter of 34 units?

• 106.76 units

• 68π units

• 34π units

• 170 units

For a square inscribed in a circle, if one side of the square is 8 units, what is the circle's diameter?

• 8√2 units

• 8 units

• 16 units

• 11.2 units

What is the approximate circumference of a circle with a diameter of 11.2 units?

• 35.168 units

• 22.4 units

• 11.2π units

• 56.336 units