Understanding Circle Measurements

Nelson introduces a lesson on distinguishing between the circumference and area of circles for seventh-grade math. The lesson covers the formulas for calculating the area and circumference of a circle, emphasizing the importance of understanding when to use each formula. Through a scenario involving a merry-go-round, students analyze claims about circle measurements, deciding whether the situation involves area or circumference. The lesson concludes with a reminder to apply the correct formula based on the context.

What is the main objective of the lesson on distinguishing circumference and area?

• To calculate the volume of a circle

• To learn about different shapes

• To decide whether a situation involves area or circumference and use the correct formula

• To memorize the formulas for circumference and area

Which formula is used to calculate the area of a circle?

• Diameter times pi

• Radius squared times pi

• Two times radius times pi

• Radius times diameter

What is the value of pi approximately used in these calculations?

• 4.14

• 3.14

• 2.14

• 5.14

How is the circumference of a circle related to its diameter?

• Circumference is half the diameter

• Circumference is the diameter times pi

• Circumference is the diameter squared

• Circumference is the diameter divided by pi

Which formula can be used to find the circumference if the radius is known?

• Radius squared times pi

• Diameter times pi

• Two times radius times pi

• Radius times pi

What is the relationship between the radius and diameter of a circle?

• Diameter is three times the radius

• Diameter is half the radius

• Diameter is the same as the radius

• Diameter is twice the radius

In the scenario analysis, what does Claire claim about the merry-go-round?

• The area is four pi square feet

• The diameter is four feet

• The radius is four feet

• The circumference is four pi feet

Why does the narrator believe Claire's estimation is more accurate?

• Because the child is shorter than the merry-go-round

• Because the child is taller than the merry-go-round

• Because the child could stretch from the edge to the middle

• Because the child could stretch across the merry-go-round

What is the correct circumference of the merry-go-round according to Claire's estimation?

• 8 pi feet

• 12 pi feet

• 16 pi feet

• 4 pi feet

What should be the first step in solving a problem involving circles?

• Use the area formula

• Find the radius

• Determine if the problem involves area or circumference

• Calculate the diameter