Calculate Square Perimeter: Solving (√3·√12-5)²·3² Side Length Problem

Square Perimeter with Radical Simplification

A square has a side length of

(3125)232 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 .

Calculate its perimeter.

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Determine the perimeter of the square
00:04 Start by calculating the side length
00:09 Square root of number(A) times square root of number(B)
00:12 Equals the square root of their product (A times B)
00:17 Let's use this formula in our exercise
00:24 Calculate the product
00:32 Calculate the root and substitute
00:37 Solve the parentheses
00:44 1 to the power of any number always equals 1
00:52 This is the side length of the square
00:55 In a square all sides are equal
01:00 Calculate the perimeter
01:03 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

A square has a side length of

(3125)232 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 .

Calculate its perimeter.

2

Step-by-step solution

To calculate the perimeter of a square, we need to first determine the length of one side and then use the formula for the perimeter of a square, which is given by 4×side length 4 \times \text{side length} .

The side length is given as (3125)232 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 . Let's simplify this expression step by step:

  • First, simplify the square roots: 3 \sqrt{3} and 12 \sqrt{12} .

    • 12=4×3=4×3=2×3 \sqrt{12} = \sqrt{4 \times 3} = \sqrt{4}\times \sqrt{3} = 2 \times \sqrt{3}
    • Thus, 3×12=3×2×3=2×3=6 \sqrt{3} \times \sqrt{12} = \sqrt{3} \times 2 \times \sqrt{3} = 2 \times 3 = 6 .
  • Next, substitute back into the expression: (65)232 (6 - 5)^2 \cdot 3^2 .
  • Simplify inside the parentheses: 65=1 6 - 5 = 1 , so we have 1232 1^2 \cdot 3^2 .
  • Calculate the squares: 12=1 1^2 = 1 and 32=9 3^2 = 9 .
  • Multiply the results: 1×9=9 1 \times 9 = 9 .

The side length of the square is therefore 9 9 .

Thus, the perimeter of the square is:

  • 4×9=36 4 \times 9 = 36 .

Therefore, the perimeter of the square is 36 36 .

3

Final Answer

36

Key Points to Remember

Essential concepts to master this topic
  • Radical Property: Use ab=ab \sqrt{a} \cdot \sqrt{b} = \sqrt{ab} to simplify products
  • Technique: Factor perfect squares: 12=4×3=23 \sqrt{12} = \sqrt{4 \times 3} = 2\sqrt{3}
  • Check: Verify side length 9 gives perimeter 4×9=36 4 \times 9 = 36

Common Mistakes

Avoid these frequent errors
  • Calculating perimeter before simplifying the side length expression
    Don't multiply by 4 before simplifying (3125)232 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 = wrong formula application! This leads to complex calculations with radicals. Always simplify the side length completely first, then multiply by 4.

Practice Quiz

Test your knowledge with interactive questions

What is the result of the following equation?

\( 36-4\div2 \)

FAQ

Everything you need to know about this question

Why can't I just multiply the whole expression by 4 right away?

+

You need to find the actual side length first! The expression (3125)232 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 simplifies to 9, so the perimeter is 4 × 9 = 36, not 4 times the complex expression.

How do I simplify 312 \sqrt{3} \cdot \sqrt{12} ?

+

Use the property ab=ab \sqrt{a} \cdot \sqrt{b} = \sqrt{ab} ! So 312=36=6 \sqrt{3} \cdot \sqrt{12} = \sqrt{36} = 6 . Or factor: 12=23 \sqrt{12} = 2\sqrt{3} , so 323=23=6 \sqrt{3} \cdot 2\sqrt{3} = 2 \cdot 3 = 6 .

What if I get a negative number inside the parentheses?

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In this problem, 312=6 \sqrt{3}\cdot\sqrt{12} = 6 and 65=1 6 - 5 = 1 , which is positive! If you got negative, double-check your radical multiplication.

Why does (1)232 (1)^2 \cdot 3^2 equal 9?

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Because any number to the power of 2 means multiply by itself: 12=1×1=1 1^2 = 1 \times 1 = 1 and 32=3×3=9 3^2 = 3 \times 3 = 9 . Then 1×9=9 1 \times 9 = 9 .

How can I check if my final answer is correct?

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Substitute back! If the side length is 9, then the perimeter should be 4×9=36 4 \times 9 = 36 . Also verify that (3125)232=(65)29=19=9 (\sqrt{3}\cdot\sqrt{12}-5)^2\cdot3^2 = (6-5)^2\cdot9 = 1\cdot9 = 9

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