Topic Details (Notes format)

How to Calculate the Area of a Circle

Subject: Mathematics

Book: Maths Mastery

The area of a circle is given by the formula A = πr², where r is the radius—the distance from the center to the circumference. If you have a circle with radius 5 cm, its area is π × 5² = 25π cm². In practical terms, you might need to measure the space a circular rug covers or the cross-sectional area of a circular pipe. Knowing how to apply A = πr² is foundational in geometry, engineering, and architecture. Pairing this knowledge with circumference or volume formulas further expands your capability to handle circular shapes in diverse projects and daily scenarios.

Practice Questions

The sum of the squares of two consecutive integers is 145. What are the integers?

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

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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 slope of a line passing through the points (2, 3) and (4, 7)?

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If a = 2 and b = 3, what is the value of (a^2 + b^2)?

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What is the square root of 144?

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If 5x - 2 = 13, what is the value of x?

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A sphere has a radius of 7 cm. What is its volume?

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What is the HCF of 72 and 120?

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If 2x - 3 = 7, what is the value of x?

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