How to calculate circle skirt radius/Detailed explanation on how to cut circle skirt.

Summary

In this 'All About Sewing' lesson, the instructor teaches viewers how to calculate the radius for different degrees of circle skirts, including 360, 270, 180, and 90-degree styles. The key formula involves dividing the waist measurement by 6.28, with adjustments for skirt degree and fabric stretch. The tutorial simplifies the math, making it accessible for sewing enthusiasts to create full, half, quarter-circle skirts, and more, with practical tips for fabric cutting and fitting.

Takeaways

• 📐 The lesson focuses on calculating the radius for different types of circle skirts using specific formulas.
• 🧵 For a 360-degree full circle skirt, the radius is found by dividing the waist measurement by 6.28.
• 🔄 The 360-degree skirt forms a full circle, with the radius being the distance from the waist to the hem.
• ✂️ To get a perfect fit for non-stretch fabric, subtract 2 inches from the waist measurement before dividing by 6.28.
• 📏 A 270-degree skirt uses a similar method but with an additional factor of 1.33 in the formula.
• 💡 The 1.33 factor comes from dividing three-quarters of a full circle (3/4) to adjust the formula for a 270-degree skirt.
• ➗ For a 180-degree half-circle skirt, divide the waist measurement by 3.14 to find the radius.
• 🔍 The 180-degree formula simplifies the full circle formula by considering half of the circle's circumference.
• 🔄 A 90-degree quarter-circle skirt requires multiplying the waist measurement by 2 and dividing by 3.14 to find the radius.
• 🧮 Each formula is derived from the basic concept of calculating the circumference of a circle, adapting it to different skirt designs.

Q & A

What is the primary focus of the 'All About Sewing: Circle Skirt Lesson One'?

The primary focus of the lesson is to teach the mathematics involved in creating circle skirts, specifically the formula for calculating the radius needed for different degrees of circle skirts.

What is the formula used to calculate the radius for a 360-degree circle skirt?

For a 360-degree circle skirt, the formula to calculate the radius is to divide the waist measurement by 6.28.

Why might you need to subtract 2 inches from the waist measurement when sewing a stretch fabric circle skirt?

You might need to subtract 2 inches from the waist measurement when sewing a stretch fabric circle skirt to ensure a perfect fit around the waist without needing any side or back seams or zippers.

What is the significance of the number 6.28 in the context of the sewing lesson?

The number 6.28 is used in the formulas because it represents two times pi (2π), which is the constant used to calculate the circumference of a circle.

How does the formula for a 270-degree circle skirt differ from that of a 360-degree skirt?

For a 270-degree circle skirt, the waist measurement is multiplied by 1.33 and then divided by 6.28, as opposed to just dividing by 6.28 for a 360-degree skirt.

What mathematical concept is used to derive the radius for a 180-degree circle skirt?

The radius for a 180-degree circle skirt is derived by dividing the waist measurement by 3.14, which is half of 6.28, representing half of the full circle's circumference.

Why is the number 3.14 used in the formula for a 180-degree circle skirt?

The number 3.14 is used because it represents π, and since a 180-degree circle skirt is half of a full circle, the formula uses half of 6.28 (which is 2π).

What is the formula for calculating the radius of a 90-degree circle skirt?

For a 90-degree circle skirt, the formula is to multiply the waist measurement by 4 and then divide by 6.28, or alternatively, divide the waist measurement by 3.14 after considering the full circle formula.

How does the instructor explain the transition from the full circle formula to the half and quarter circle formulas?

The instructor explains the transition by demonstrating how the full circle formula is adjusted by dividing by 2 for the half circle (180 degrees) and by 4 for the quarter circle (90 degrees), reflecting the proportional parts of the circle being used.

What additional advice does the instructor give for cutting out the circle skirt pieces from the fabric?

The instructor advises that for non-stretch fabrics, the material should be folded into four to cut out the circle, and for stretch fabrics, one might need to adjust the waist measurement accordingly to avoid seams or zippers.