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 x^3 - 3x^2 + 4 = 0, what is one root of the equation?

View Question

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

View Question

If x:y = 4:5 and y:z = 2:3, what is x:z?

View Question

If x^2 - 5x + 6 = 0, what are the roots?

View Question

If the length of a rectangle is doubled and the width is halved, what is the change in area?

View Question

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

View Question

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

View Question

If x - y = 5 and x + y = 15, what is the value of x?

View Question

What is the sum of the first 10 positive even numbers?

View Question

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

View Question