Topic Details (Notes format)

How to Solve Proportions (Cross-Multiplication)

Subject: Mathematics

Book: Maths Mastery

Proportions equate two ratios, like a/b = c/d. Cross-multiplication states ad = bc. For example, if 2/5 = x/15, then 2 × 15 = 5 × x, meaning 30 = 5x, so x = 6. Proportions answer real-world questions: “If 2 liters costs ₹100, what does 5 liters cost?” or “If 3 out of 10 students prefer a subject, how many out of 50 might prefer it?” The technique is vital for scaling recipes, resizing images, or solving geometry similarity. Consistent practice ensures you can set up and solve ratio-based statements in a single, efficient step.

Practice Questions

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

View Question

The sides of a triangle are 5 cm, 12 cm, and 13 cm. What type of triangle is it?

View Question

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

View Question

If the sides of a triangle are 6 cm, 8 cm, and 10 cm, what is the area of the triangle?

View Question

If x = 3 and y = 4, what is the value of x^2 + y^2?

View Question

What is the square root of 144?

View Question

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

View Question

If the radius of a circle is doubled, what happens to its area?

View Question

If the product of two numbers is 120 and their sum is 26, what are the numbers?

View Question

If sin(A) = 3/5 and cos(B) = 5/13, where A and B are acute angles, what is sin(A+B)?

View Question