Solve for x in the Triangle with Sides x, x+1, and x+2

Question

Calculate x according to the figure shown below below.

x>0

x+1x+1x+1xxxx+2x+2x+2

Video Solution

Solution Steps

00:00 Find X
00:03 Use the Pythagorean theorem in the triangle
00:08 Substitute appropriate values and solve for X
00:14 Open parentheses properly
00:22 Simplify where possible
00:28 Collect terms and arrange the equation
00:46 Find the possible solutions for X
00:52 X must be greater than 0, therefore this solution is not logical
00:57 And this is the solution to the question

Step-by-Step Solution

To find x x in the given triangle, let's apply the Pythagorean Theorem. The squared lengths of the triangle's legs and hypotenuse are related by this equation:

(x+1)2+x2=(x+2)2 (x+1)^2 + x^2 = (x+2)^2

First, expand each term:

  • (x+1)2=x2+2x+1 (x+1)^2 = x^2 + 2x + 1
  • x2=x2 x^2 = x^2
  • (x+2)2=x2+4x+4 (x+2)^2 = x^2 + 4x + 4

Plug these into the Pythagorean Theorem equation:

(x2+2x+1)+x2=x2+4x+4 (x^2 + 2x + 1) + x^2 = x^2 + 4x + 4

Combine like terms:

2x2+2x+1=x2+4x+4 2x^2 + 2x + 1 = x^2 + 4x + 4

Rearrange the equation to isolate terms on one side:

2x2+2x+1x24x4=0 2x^2 + 2x + 1 - x^2 - 4x - 4 = 0

Simplify to get a quadratic equation:

x22x3=0 x^2 - 2x - 3 = 0

Now, solve for x x using factoring. Look for two numbers that multiply to 3-3 and add to 2-2. These numbers are 3-3 and 11:

(x3)(x+1)=0 (x - 3)(x + 1) = 0

Set each factor equal to zero:

  • x3=0x=3 x - 3 = 0 \Rightarrow x = 3
  • x+1=0x=1 x + 1 = 0 \Rightarrow x = -1

Given the condition x>0 x > 0 , the valid solution is:

x=3 x = 3

Answer

x=3 x=3