Circles Skills Practice

Which is the correct formula for the area of a circle?

Answer explanation

The correct formula for the area of a circle is A = πr^2, where r is the radius of the circle. This formula is derived from the definition of the area of a circle as π times the square of the radius.

Tags

TEKS.MATH.7.9B

If the radius of a circle is 7 cm, what is the diameter?

• 3.5 cm

• 14 cm

• 21 cm

• 49 cm

Answer explanation

The diameter of a circle is twice the radius, so if the radius is 7 cm, the diameter is 2 * 7 = 14 cm. Therefore, the correct answer is 14 cm.

Tags

TEKS.MATH.7.9B

A circle has a diameter of 10 inches. What is the radius?

• 5 inches

• 10 inches

• 15 inches

• 20 inches

Answer explanation

To find the radius of a circle from the diameter, divide the diameter by 2. Therefore, the radius is 10 inches / 2 = 5 inches.

Tags

TEKS.MATH.7.9B

• 18.84 cm

• 37.68 cm

• 12 cm

• 28.26 cm

Answer explanation

The circumference of a circle is calculated using the formula: Circumference = 2 * π * radius. Substituting the values, Circumference = 2 * 3.14 * 6 = 37.68 cm. Therefore, the correct answer is 37.68 cm.

Tags

TEKS.MATH.7.9B

A circle has a radius of 4.3 cm. Find the area of that circle. Round to the nearest hundredth.

Answer explanation

To find the area of a circle, use the formula A = πr^2. Substituting r = 4.3 cm, A = π(4.3)^2 ≈ 58.09 cm^2. Therefore, the correct answer is 58.09 cm^2.

Tags

TEKS.MATH.7.9B

Find the circumference of the garden shown in the scale drawing below.

• 628 feet

• 200 feet

• 100 feet

• 542 feet

Answer explanation

To find the circumference, we need to multiply the scale factor by the actual circumference. Scale factor = 1 inch = 10 feet. Actual circumference = 62.8 inches * 10 = 628 feet.

Tags

TEKS.MATH.7.9B

What is the area of this circle?

Answer explanation

The correct answer is 1520.53 cm^2, which is the area of the circle. The formula for the area of a circle is A = πr^2.

Tags

TEKS.MATH.7.9B

Find the circumference to the nearest foot.

• 231 feet squared

• 132 feet squared

• 321 feet squared

• 123 feet squared

Answer explanation

The correct answer is 132 feet squared because circumference is a linear measurement and should not be squared. It should be expressed in feet.

Tags

TEKS.MATH.7.9B

What is/are the formula(s) to find the area of a circle?

• πr²

• 2πr

• √π

Answer explanation

The formula to find the area of a circle is πr^2, where r is the radius of the circle.

A pond has a diameter of 12 feet. What is its radius?

• 12 feet

• 6 feet

• 24 feet

Answer explanation

To find the radius, divide the diameter by 2. So, 12 feet ÷ 2 = 6 feet. Therefore, the radius of the pond is 6 feet.