√ Square Root of 400 = 20
The square root of 400 is a value that when multiplied by itself gives 400. Learn 5 different methods to calculate √400 with step-by-step explanations.
What Is √400 and Why It Matters
The square root of 400 is 20 because 20 × 20 = 400. This makes 400 a perfect square, one of the most fundamental numbers in mathematics. The square root 20 is an integer, making calculations simple and exact.
Understanding √400 helps build a strong foundation in algebra, geometry, and advanced mathematics. Whether you're a student learning square roots, a teacher preparing lessons, or a professional needing quick math references, this guide covers everything you need to know.
5 Ways to Calculate √400
Choose the method that works best for you, from simple mental math to advanced approximation techniques.
Mental Math (Multiplication)
Find a number that multiplies by itself to equal 400. Since 20 × 20 = 400, the answer is 20.
Prime Factorization
Prime factors: 400 = 2 × 2 × 2 × 2 × 5 × 5. Pair the factors and multiply one from each pair: 20.
Long Division
Pair digits from right: 400 → 400. Find largest square ≤ 400: 20² = 400. Answer: 20.000000
Newton-Raphson (Iterative)
Formula: x₁ = (x₀ + n/x₀)/2. Starting with 20: iterations converge to 20.
Scientific Calculator
Press √, then 400, then = or Enter. Result: 20.000000.
Method Comparison
| Method | Best For | Result | Difficulty |
|---|---|---|---|
| Mental Math | Quick estimates | 20 | Easy |
| Prime Factorization | Simplifying radicals | 20 | Medium |
| Long Division | Exact decimals | 20.000000 | Hard |
| Newton-Raphson | Programming | 20 | Hard |
| Calculator | Everyday use | 20.000000 | Easy |
Real-World Uses of √400
Geometry & Area
A square with area 400 cm² has side length 20 cm. This is a classic example used in math classes worldwide.
Construction & Architecture
Builders and architects use √400 to calculate diagonal measurements, ensure right angles, and determine material quantities.
Statistics & Data Science
Standard deviation, variance, and other statistical measures frequently use square root calculations for data analysis.
Physics & Engineering
Square roots are essential in calculating velocity, acceleration, electrical resistance, and many scientific formulas.
Continue Your Learning Journey
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Frequently Asked Questions
Practice Problems
Final Thoughts
The square root of 400 is 20. Since 20 × 20 = 400, this is a perfect square that's essential in mathematics.
We've explored 5 different methods to calculate √400, from simple mental math to advanced iterative techniques. Each method offers a unique approach to understanding this fundamental mathematical concept.
"Mastering square roots opens the door to advanced mathematics and real-world problem solving."