Circle Geometry Concepts

This video tutorial covers the basics of circles, including the concepts of circumference, radius, and diameter. It explains how to calculate the circumference and area of a circle using Pi, with practical examples. The tutorial also explores semi-circles and quarter circles, demonstrating how to calculate their perimeter and area. The video aims to clarify common confusions between circumference and area formulas, providing a comprehensive understanding of circle geometry.

What is the term used for the perimeter of a circle?

• Area

• Circumference

• Radius

• Diameter

What is the formula for the circumference of a circle?

• πr²

• r²

• 2πr

• πd

What is the radius of a circle?

• The area of the circle

• The distance around the circle

• The distance from the center to the edge

• The distance across the circle through the center

What is the formula for the area of a circle?

• πd

• r²

• πr²

• 2πr

In the formula for circumference, where is the number 2 placed?

• It is not used

• At the beginning of the formula

• At the end of the formula

• In the middle of the formula

What is the circumference of a circle with a radius of 5 using π as 3.14?

• 78.5 meters

• 15.7 meters

• 31.4 meters

• 25 meters

What is the area of a circle with a radius of 5 using π as 3.14?

• 31.4 meters²

• 15.7 meters²

• 78.5 meters²

• 25 meters²

For a circle with a diameter of 30, what is the radius?

• 60

• 15

• 30

• 45

What is the circumference of a circle with a radius of 15 using π as 3.14?

• 31.4 cm

• 188.4 cm

• 47.1 cm

• 94.2 cm

What is the area of a circle with a radius of 15 using π as 3.14?

• 471 cm²

• 1413 cm²

• 353.25 cm²

• 706.5 cm²