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Finding the Fourth Proportional to 318.79, 439.59 and 231.40

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Solution

The fourth proportional to 318.79, 439.59 and 231.40 is: 319.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    318.79 : 439.59 = 231.40 : x
  2. Step 2: Convert to fraction form
    318.79/439.59 = 231.40/x
  3. Step 3: Cross multiply
    318.79x = 439.59 × 231.40
  4. Step 4: Simplify right side
    318.79x = 101,721.13
  5. Step 5: Solve for x
    x = 101,721.13/318.79
  6. Step 6: Final answer
    x = 319.09

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.