Topic Details (Notes format)

How to Calculate the Percentage of a Number?

Subject: Mathematics

Book: Maths Mastery

Percentages are central to countless real-world applications—from calculating exam marks to determining discounts and interest rates. The general formula to find a percentage is: (Part / Whole) × 100%. However, if you already know the rate and the whole, use Percentage of a Number = (Rate ÷ 100) × Whole. For example, to calculate 20% of 150, convert 20% to 0.20, then multiply: 0.20 × 150 = 30. This concept is pivotal in areas like finance and data analysis, so practice by computing percentages for tips in restaurants, taxes on shopping bills, or proportionate contributions in group projects. Mastering this skill builds a strong foundation for advanced percentage operations such as percentage increase, decrease, and compound interest calculations.

Practice Questions

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

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 2a + b = 10 and a - b = 4, what is the value of a?

View Question

What is the sum of all angles in a hexagon?

View Question

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

View Question

What is the length of the diagonal of a square with a side length of 7 cm?

View Question

What is the value of log₃(27)?

View Question

The base of a triangle is 10 cm and its height is 6 cm. What is its area?

View Question

If a square has a perimeter of 64 cm, what is its area?

View Question

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

View Question