Circles Flashcard

Front

What is the formula for the area of a circle?

Back

Front

What does r represent in the formula A = π·r^2?

Back

In the formula A = π·r^2, r represents the radius of the circle.

Front

What is the circumference of a circle?

Back

Front

How do you find the area of a sector of a circle?

Back

Front

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

Back

Front

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

Back

If r = 5 cm, then the area A = π·(5)^2 = 25π cm² ≈ 78.54 cm².

Front

What is the formula for the circumference of a circle in terms of diameter?

Back

Front

What is the area of a circle with a radius of 10 inches?

Back

If r = 10 inches, then the area A = π·(10)^2 = 100π in² ≈ 314.16 in².

Front

How do you convert degrees to radians?

Back

Front

What is the area of a sector with a radius of 4 cm and an angle of 90 degrees?

Back

Using the sector area formula: @@A = rac{90}{360}·π·(4)^2 = rac{1}{4}·16π = 4π cm² ≈ 12.57 cm².