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Finding the Fourth Proportional to 667.67, 921.33 and 387.90

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Solution

The fourth proportional to 667.67, 921.33 and 387.90 is: 535.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.67 : 921.33 = 387.90 : x
  2. Step 2: Convert to fraction form
    667.67/921.33 = 387.90/x
  3. Step 3: Cross multiply
    667.67x = 921.33 × 387.90
  4. Step 4: Simplify right side
    667.67x = 357,383.91
  5. Step 5: Solve for x
    x = 357,383.91/667.67
  6. Step 6: Final answer
    x = 535.27

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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.