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Thought-Process to Discover Knowledge

Welcome to nubtrek.

Books and other education websites provide "matter-of-fact" knowledge. Instead, nubtrek provides a thought-process to discover knowledge.

In each of the topic, the outline of the thought-process, for that topic, is provided for learners and educators.

Read in the blogs more about the unique learning experience at nubtrek.

In the topic "mensuration", the foundation focuses on learning

•  what is measurement standard?

•  Absolute and Derived Standards

In this page, the formula to find circumference of a circle is introduced.

click on the content to continue..

Which of the following is a meaning for the word "circumference"?

• enclosing boundary
• enclosing boundary
• drop over a net

The answer is "enclosing boundary". The word "circumference" is from root words with meaning circum-(around; about) and -ferre(carrying; bearing).

What is the term used to refer "the perimeter of a curved shape"?

• Pronunciation : Say the answer once

The answer is "circumference". Perimeter is used for shapes of straight lines and circumference is used for shaped of curved lines.

We have learned about measurement of objects in real-life, or a line segment of arbitrary length. Some of the learnings are:

•  The length of an object can be an integer value in the unit of measurement. eg: 2cm

•  The length of an object need not be exactly an integer value in the unit of measurement. It can be given in smaller unit of length. eg: Length of a pencil is 2cm 5mm or =25mm or =2.5cm

•  The length of an object can be a decimal number in which the decimals do not repeat or do not end. The practical measure of the length is limited by the accuracy of the instrument used in measuring. eg: Length of a pencil is 2.512847cdots cm.

Similarly, the circumference of a circle of 1cm diameter is a decimal number in which the decimals do not repeat or do not end. That number is approximately 3.14cm or 22/7 cm.

What is the circumference of a circle of diameter 1cm?

• pi cm
• approximately 22/7 cm
• approximately 3.14cm
• all the above
• all the above

The answer is "all the above"

Circumference of a circle of diameter 1cm is represented as pi. For a circle of diameter d cm or r cm, the circumference is pi d  or 2 pi r cm.

What is the circumference of a circle of 7cm radius?
Approximate pi=22/7

• 44cm
• 44cm
• 22cm

The answer is "44cm"

Circumference of a Circle: : Circumference = 2 pi r and =pi d

r is the radius of the circle

d is the diameter of the circle

Solved Exercise Problem:

What is the circumference of a circle of 1/pi cm diameter?

• 1cm
• 1cm
• pi cm

The answer is "1cm"

slide-show version coming soon