Question

problems 7–9: determine whether each measurement represents the radius, diameter, or circumference, and record it in the appropriate column of the table. then determine the exact lengths of the other two measurements of the circle.

	measurement	radius	diameter	circumference
8.	the fence around a circular pool is 76 feet long.	12.10	24.20	76
9.	the center to the edge of a small plate measures 60 millimeters.

Explanation:

Step1: Analyze Problem 7

The tire's height is its diameter (since height of a tire is the distance across, diameter). So diameter \( d = 14 \) feet. Radius \( r=\frac{d}{2}=\frac{14}{2} = 7 \) feet. Circumference \( C=\pi d=3.14\times14 = 43.96 \) feet.

Step2: Analyze Problem 8

The fence length is the circumference (\( C = 76 \) feet). Diameter \( d=\frac{C}{\pi}=\frac{76}{3.14}\approx24.20 \) feet. Radius \( r=\frac{d}{2}=\frac{24.20}{2}=12.10 \) feet.

Step3: Analyze Problem 9

Center to edge is radius (\( r = 60 \) mm). Diameter \( d = 2r=120 \) mm. Circumference \( C=\pi d = 3.14\times120 = 376.8 \) mm.

Answer:

Problem 7:

• Radius: \( 7 \) feet
• Diameter: \( 14 \) feet
• Circumference: \( 43.96 \) feet

Problem 8:

• Radius: \( 12.10 \) feet
• Diameter: \( 24.20 \) feet
• Circumference: \( 76 \) feet

Problem 9:

• Radius: \( 60 \) millimeters
• Diameter: \( 120 \) millimeters
• Circumference: \( 376.8 \) millimeters