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Finding the Fourth Proportional to 642.38, 885.66 and 476.31

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Solution

The fourth proportional to 642.38, 885.66 and 476.31 is: 656.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.38 : 885.66 = 476.31 : x
  2. Step 2: Convert to fraction form
    642.38/885.66 = 476.31/x
  3. Step 3: Cross multiply
    642.38x = 885.66 × 476.31
  4. Step 4: Simplify right side
    642.38x = 421,848.71
  5. Step 5: Solve for x
    x = 421,848.71/642.38
  6. Step 6: Final answer
    x = 656.70

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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.