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

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

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What is the area of an equilateral triangle with side length 10 cm?

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What is the sum of all angles in a hexagon?

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A triangle has angles 60°, 60°, and 60°. What type of triangle is it?

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The sum of the reciprocals of two numbers is 1/4. If one number is 12, what is the other?

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The perimeter of a rectangle is 50 cm, and its length is 15 cm. What is its width?

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The sides of a triangle are 13 cm, 14 cm, and 15 cm. What is its area?

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If x:y = 2:3 and z:y = 4:3, what is x:z?

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What is the HCF of 72 and 120?

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The ratio of two numbers is 3:5, and their sum is 64. What are the numbers?

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