area and circumference of circles

Front

What is the formula for the area of a circle?

Back

Area = πr², where r is the radius.

Front

What is the formula for the circumference of a circle?

Back

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

Front

If a circle has a diameter of 16 cm, what is its radius?

Back

Radius = Diameter / 2 = 16 cm / 2 = 8 cm.

Front

Calculate the area of a circle with a radius of 8 cm.

Back

Area = π(8 cm)² = 201.06 cm² (approximately).

Front

What is the circumference of a circle with a radius of 1.5 feet?

Back

Circumference = 2π(1.5 ft) = 9.42 ft (approximately).

Front

If the circumference of a circle is 37.68 cm, what is its diameter?

Back

Diameter = Circumference / π = 37.68 cm / π ≈ 12 cm.

Front

What is the relationship between diameter and radius?

Back

Diameter = 2 × Radius.

Front

How do you convert diameter to radius?

Back

Radius = Diameter / 2.

Front

If Randy's garden has a radius of 1.5 feet, how much edging does he need to buy?

Back

He needs to buy approximately 9.42 feet of edging.

Front

What is the cost of edging per foot if Randy's garden costs $0.75 per foot?

Back

Cost = $0.75 per foot.