Calculate Square Perimeter Using Diagonal Expression: 3√2×(3²-2³)-2√2

Question

ABCD is a square.

The length of the diagonal:
32×(3223)22 3\sqrt{2}\times\left(3^2-2^3\right)-2\sqrt{2}

AAABBBCCCDDDWhat is the perimeter of the square ABCD?

Video Solution

Solution Steps

00:00 Find the perimeter of the square
00:05 In a square all sides are equal, we'll mark them as A
00:08 In a square all angles are right angles
00:11 We'll use the Pythagorean theorem in triangle ADB
00:21 We'll substitute appropriate values according to the given and solve for A
00:44 We'll solve the powers and substitute
00:59 Always solve parentheses first
01:20 Subtract
01:23 The square root of any number squared equals the number itself
01:26 We'll isolate side A
01:34 This is the length of side A
01:41 The perimeter of a square equals 4 times the side (because all sides are equal)
01:47 We'll substitute the length A we found and solve for the perimeter
01:50 And this is the solution to the question

Step-by-Step Solution

The problem involves the square ABCD, and we need to determine its perimeter, given the expression for the length of its diagonal. Here's the step-by-step solution:

Let's denote the side of the square ABCD as s s . The diagonal of a square can be calculated using Pythagoras' theorem as:

  • d=s2 d = s\sqrt{2}

The problem provides an expression for the length of the diagonal:

  • 32×(3223)22 3\sqrt{2}\times(3^2-2^3)-2\sqrt{2}

Let's simplify this expression step by step.

First, calculate the powers:

  • 32=9 3^2 = 9

  • 23=8 2^3 = 8

Subtract these values:

  • 3223=98=1 3^2 - 2^3 = 9 - 8 = 1

Substitute back into the expression for the diagonal:

  • 32×122 3\sqrt{2} \times 1 - 2\sqrt{2}

This simplifies to:

  • 3222 3\sqrt{2} - 2\sqrt{2}

  • (32)2=12=2 (3 - 2)\sqrt{2} = 1\sqrt{2} = \sqrt{2}

So, the length of the diagonal is 2 \sqrt{2} .

We know from the formula for the diagonal of a square that d=s2 d = s\sqrt{2} . Given d=2 d = \sqrt{2} , we can equate:

  • s2=2 s\sqrt{2} = \sqrt{2}

Thus:

  • s=1 s = 1

Therefore, the perimeter of the square ABCD is:

  • 4×s=4×1=4 4 \times s = 4 \times 1 = 4

Hence, the perimeter of the square ABCD is 4.

Answer

4