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Finding the Fourth Proportional to 439.14, 655.25 and 390.42

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Solution

The fourth proportional to 439.14, 655.25 and 390.42 is: 582.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.14 : 655.25 = 390.42 : x
  2. Step 2: Convert to fraction form
    439.14/655.25 = 390.42/x
  3. Step 3: Cross multiply
    439.14x = 655.25 × 390.42
  4. Step 4: Simplify right side
    439.14x = 255,820.75
  5. Step 5: Solve for x
    x = 255,820.75/439.14
  6. Step 6: Final answer
    x = 582.55

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.