Question

Mark wants to find the area of a circle with a diameter of 8 cm. Which expressions can he use to find the area of the circle in square centimeters? Choose all the correct answers.

a) 2π × 4
b) 8π
c) 4 × 4π
d) 8^2 × π
e) 4^2 × π

Answer 1

Mark can use the expressions c) 4 × 4π and e) 4² × π to calculate the area of a circle with an 8 cm diameter, as both correspond to the formula A = πr² with a radius of 4 cm.

Step-by-step explanation:

Mark wants to find the area of a circle with a diameter of 8 cm. To calculate the area, the formula A = πr² is used, where π is approximately 3.14159 and r is the radius of the circle. Since the diameter is 8 cm, the radius (r) would be half of that, which is 4 cm. Now, we can identify the correct expressions Mark can use:

• c) 4 × 4π corresponds to (radius)² × π, which is exactly the area formula.
• e) 4² × π is another way of writing the previous expression and also represents the correct area (4 cm)² × π.

The other options do not represent the formula for the area of a circle, as they do not involve squaring the radius. The correct expressions that Mark can use to find the area of the 8 cm diameter circle in square centimeters are c) 4 × 4π and e) 4² × π.