Topic Details (Notes format)

How to Calculate the Circumference of a Circle

Subject: Mathematics

Book: Maths Mastery

The circumference of a circle—the distance around its outer edge—is pivotal in measuring circular objects like wheels, plates, or rings. The formula is C = 2πr (or πd), where r is the radius and d is the diameter. For example, if the diameter is 10 cm, the circumference is π × 10 = 10π cm. This calculation is vital in fields such as manufacturing tires, designing circular pathways, or analyzing circular motion in physics. By pairing circumference with area, you gain a holistic grasp of circle properties essential in academic and real-world tasks.

Practice Questions

A number is increased by 20% and then decreased by 10%. What is the net change?

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A rectangle has an area of 48 cm² and a length of 8 cm. What is its width?

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If a = 4 and b = 5, what is the value of (a+b)^2?

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A sum of money doubles itself in 5 years at simple interest. What is the rate of interest?

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A car travels 240 km in 4 hours. What is its average speed?

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A train 120 meters long is moving at a speed of 54 km/h. How long will it take to pass a pole?

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If the radius of a circle is 7 cm, what is its circumference?

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If x² - 9x + 18 = 0, what are the roots of the equation?

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What is the probability of drawing an ace from a standard deck of 52 cards?

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What is the sum of the first 50 positive integers?

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