Meg is making ribbons for the country fair. she needs to glue edging around the outside of the circular part of the ribbon shown. about how many centimeters of edging does she need?
5 cm
7 cm
9 cm
28 cm
Meg is making ribbons for the country fair. she needs to glue edging around the outside of the circular part of the ribbon shown. about how many centimeters of edging does she need? (1 point)
5 cm
7 cm
9 cm
28 cm
What is the circumference of the circle?
1.5cm, but I think is 5 I guess
To solve this problem, we need to find the circumference of the circular part of the ribbon. The circumference is the distance around the circle.
The formula to find the circumference of a circle is C = 2πr, where C is the circumference, π is a mathematical constant (approximately 3.14159), and r is the radius of the circle.
However, we don't have the radius of the circular part of the ribbon, but we do have the diameter. Diameter is the distance across the circle, passing through the center. The relationship between the diameter and the radius is that the diameter is twice the length of the radius.
Since the ribbons shown are circular, it means the diameter is equal to the width of the ribbon. In this case, the width of the ribbon is 5 cm, 7 cm, 9 cm, or 28 cm.
To get the radius, we need to divide the diameter by 2. So, the radius for each width is as follows:
- For 5 cm width, radius = 5 cm / 2 = 2.5 cm
- For 7 cm width, radius = 7 cm / 2 = 3.5 cm
- For 9 cm width, radius = 9 cm / 2 = 4.5 cm
- For 28 cm width, radius = 28 cm / 2 = 14 cm
Now that we have the radius, we can use the circumference formula to find the length of the edging needed for each width of the ribbon:
- For radius 2.5 cm, circumference = 2π(2.5 cm) ≈ 15.7 cm
- For radius 3.5 cm, circumference = 2π(3.5 cm) ≈ 21.99 cm
- For radius 4.5 cm, circumference = 2π(4.5 cm) ≈ 28.27 cm
- For radius 14 cm, circumference = 2π(14 cm) ≈ 87.96 cm
Therefore, the approximately correct amount of edging needed for the circular part of the ribbon, in centimeters, would be:
- 5 cm width: 15.7 cm
- 7 cm width: 21.99 cm
- 9 cm width: 28.27 cm
- 28 cm width: 87.96 cm
Based on these calculations, the closest option is 5 cm, as the approximate edging required is 15.7 cm.