Which formula correctly describes the proportional relationship between the circumference of a circle and the diameter?(1 point)
Responses
A=πr2
upper A equals pi r squared
π=d/C
pi equals Start Fraction d over upper C
C=π/d
upper C equals Start Fraction pi over d End Fraction
C/d=π
Start Fraction upper C over d End Fraction equals pi
C=πd
Circumference = π times diameter
Use the correct formula to find the area of a circle if the diameter is 21 mi. Round to the nearest hundredths place. Use 3.14 for π.(1 point)
Responses
1,384.74 mi.2
65.94 mi.2
346.19 mi.2
131.88 mi.2
To find the area of a circle, you use the formula A = πr², where r is the radius. Since the diameter is given, we need to first find the radius by dividing the diameter by 2.
Radius (r) = Diameter / 2
r = 21 mi / 2
r = 10.5 mi
Now, we can use the formula to find the area:
A = πr²
A = 3.14 * (10.5)²
A ≈ 3.14 * 110.25
A ≈ 346.185 mi²
Therefore, the correct area of the circle when the diameter is 21 mi is approximately 346.19 mi². The closest option is 346.19 mi.²
Which of the following is the correct formula for finding the area of a circle?(1 point)
Responses
A=πd
A=πr2
A=2πr
A=C2÷4πA=πd2