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Finding the Fourth Proportional to 438.40, 658.41 and 391.42

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Solution

The fourth proportional to 438.40, 658.41 and 391.42 is: 587.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.40 : 658.41 = 391.42 : x
  2. Step 2: Convert to fraction form
    438.40/658.41 = 391.42/x
  3. Step 3: Cross multiply
    438.40x = 658.41 × 391.42
  4. Step 4: Simplify right side
    438.40x = 257,714.84
  5. Step 5: Solve for x
    x = 257,714.84/438.40
  6. Step 6: Final answer
    x = 587.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.