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Finding the Fourth Proportional to 438.30, 658.20 and 256.56

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Solution

The fourth proportional to 438.30, 658.20 and 256.56 is: 385.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.30 : 658.20 = 256.56 : x
  2. Step 2: Convert to fraction form
    438.30/658.20 = 256.56/x
  3. Step 3: Cross multiply
    438.30x = 658.20 × 256.56
  4. Step 4: Simplify right side
    438.30x = 168,867.79
  5. Step 5: Solve for x
    x = 168,867.79/438.30
  6. Step 6: Final answer
    x = 385.28

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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.