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Finding the Fourth Proportional to 667.66, 920.91 and 387.91

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Solution

The fourth proportional to 667.66, 920.91 and 387.91 is: 535.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    667.66 : 920.91 = 387.91 : x
  2. Step 2: Convert to fraction form
    667.66/920.91 = 387.91/x
  3. Step 3: Cross multiply
    667.66x = 920.91 × 387.91
  4. Step 4: Simplify right side
    667.66x = 357,230.20
  5. Step 5: Solve for x
    x = 357,230.20/667.66
  6. Step 6: Final answer
    x = 535.05

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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.