Math Problem Statement

In the given right triangle, find the side labeled x, where one leg is labeled x, the other leg is labeled x + 9, and the hypotenuse is labeled 45.

Solution

The image shows a right triangle with one leg labeled xx, the other leg labeled x+9x + 9, and the hypotenuse labeled 4545. The goal is to find the value of xx.

To solve for xx, we will use the Pythagorean Theorem, which states that for any right triangle, the square of the hypotenuse is equal to the sum of the squares of the two legs. This can be written as:

c2=a2+b2c^2 = a^2 + b^2

Here:

  • The hypotenuse c=45c = 45,
  • One leg a=xa = x,
  • The other leg b=x+9b = x + 9.

Using the Pythagorean Theorem:

452=x2+(x+9)245^2 = x^2 + (x + 9)^2

First, we calculate 45245^2:

2025=x2+(x+9)22025 = x^2 + (x + 9)^2

Now, expand (x+9)2(x + 9)^2:

(x+9)2=x2+18x+81(x + 9)^2 = x^2 + 18x + 81

Substituting back into the equation:

2025=x2+x2+18x+812025 = x^2 + x^2 + 18x + 81

Simplifying:

2025=2x2+18x+812025 = 2x^2 + 18x + 81

Now, subtract 2025 from both sides:

0=2x2+18x+8120250 = 2x^2 + 18x + 81 - 2025

Simplifying further:

0=2x2+18x19440 = 2x^2 + 18x - 1944

Now, we can divide the entire equation by 2 to simplify it:

0=x2+9x9720 = x^2 + 9x - 972

This is a quadratic equation, and we can solve for xx using the quadratic formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

For the equation x2+9x972=0x^2 + 9x - 972 = 0, a=1a = 1, b=9b = 9, and c=972c = -972. Plugging in these values:

x=9±924(1)(972)2(1)x = \frac{-9 \pm \sqrt{9^2 - 4(1)(-972)}}{2(1)} x=9±81+38882x = \frac{-9 \pm \sqrt{81 + 3888}}{2} x=9±39692x = \frac{-9 \pm \sqrt{3969}}{2} x=9±632x = \frac{-9 \pm 63}{2}

This gives two possible solutions:

  1. x=9+632=542=27x = \frac{-9 + 63}{2} = \frac{54}{2} = 27
  2. x=9632=722=36x = \frac{-9 - 63}{2} = \frac{-72}{2} = -36

Since xx represents a side length, it must be positive. Therefore, the solution is:

x=27x = 27

Would you like more details or have any questions? Here are some related questions you might consider:

  1. What would the equation look like if the hypotenuse had a different value?
  2. How would the Pythagorean Theorem apply if the triangle were isosceles?
  3. Can you use trigonometric ratios to solve this problem?
  4. How does the quadratic formula apply to solving real-world problems?
  5. What are the conditions for a quadratic equation to have real solutions?

Tip: Always check the discriminant (b24acb^2 - 4ac) in the quadratic formula to ensure the nature of the roots (real or complex).

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Pythagorean Theorem

Formulas

Pythagorean Theorem (a^2 + b^2 = c^2)
Quadratic Equation Formula x = (-b ± sqrt(b^2 - 4ac)) / 2a

Theorems

Pythagorean Theorem
Quadratic Formula

Suitable Grade Level

Grades 9-10