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Finding the Fourth Proportional to 642.17, 885.70 and 420.73

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Solution

The fourth proportional to 642.17, 885.70 and 420.73 is: 580.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.17 : 885.70 = 420.73 : x
  2. Step 2: Convert to fraction form
    642.17/885.70 = 420.73/x
  3. Step 3: Cross multiply
    642.17x = 885.70 × 420.73
  4. Step 4: Simplify right side
    642.17x = 372,640.83
  5. Step 5: Solve for x
    x = 372,640.83/642.17
  6. Step 6: Final answer
    x = 580.29

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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.