Circle Geometry Concepts

The video tutorial explains how to calculate the circumference and area of a circle using its diameter or radius. It starts with a practical problem of determining how many rounds Dajin needs to walk to cover one kilometer. The tutorial then introduces the formulas for circumference (C = πD or C = 2πR) and area (A = πR²), providing examples and exercises to reinforce understanding. The video concludes with a summary of these mathematical concepts.

What was the main concern of Dajin in the video?

• How to find the radius of a circle.

• How to calculate the area of a circle.

• How to walk one kilometer around a circular ground.

• How to calculate the volume of a sphere.

Which formula is used to calculate the circumference of a circle using its diameter?

• A = 2πD

• A = πR²

• C = πD

• C = 2πR

If the diameter of a circle is 110 meters, what is its circumference using π as 3.14?

• 345.4 meters

• 314 meters

• 220 meters

• 110 meters

How many rounds does Dajin need to complete to walk one kilometer?

• One round

• Two rounds

• Three rounds

• Four rounds

What is the formula for calculating the circumference of a circle using its radius?

• C = πD

• A = 2πD

• C = 2πR

• A = πR²

How do you find the area of a circle if you know its diameter?

• Divide the diameter by 2 to get the radius, then use A = πR²

• Use the formula A = πD²

• Multiply the diameter by π

• Use the formula A = 2πR

What is the area of a circle with a radius of 5 cm?

• 50 square cm

• 31.4 square cm

• 25 square cm

• 78.5 square cm

What is the circumference of Circle B with a radius of 10 cm?

• 100 cm

• 62.8 cm

• 31.4 cm

• 20 cm

If Circle C has a diameter of 14 meters, what is its area using π as 22/7?

• 88 square meters

• 44 square meters

• 154 square meters

• 28 square meters

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

• A = πD

• A = 2πR

• A = πR²

• A = 2πD