Circles Flashcard

Front

What is the circumference of a circle?

Back

The circumference is the distance around the circle. It can be calculated using the formula C = 2πr, where r is the radius.

Front

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

Back

C = 2πr or C = πd, where r is the radius and d is the diameter.

Front

What is a radius of a circle?

Back

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

Front

What is a diameter of a circle?

Back

The diameter is the distance across the circle through its center, equal to twice the radius.

Front

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

Back

C = 2π(5) = 31.4 cm.

Front

If the diameter of a circle is 10 cm, what is the radius?

Back

The radius is half of the diameter, so r = 10 cm / 2 = 5 cm.

Front

What is the relationship between radius and diameter?

Back

The diameter is twice the length of the radius (d = 2r).

Front

How do you find the area of a circle?

Back

The area can be calculated using the formula A = πr², where r is the radius.

Front

What is the area of a circle with a radius of 3 cm?

Back

A = π(3)² = 28.27 cm².

Front

What is π (pi)?

Back

π (pi) is a mathematical constant approximately equal to 3.14, representing the ratio of the circumference of a circle to its diameter.