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Finding the Fourth Proportional to 642, 885.54 and 421.14

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Solution

The fourth proportional to 642, 885.54 and 421.14 is: 580.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    642 : 885.54 = 421.14 : x
  2. Step 2: Convert to fraction form
    642/885.54 = 421.14/x
  3. Step 3: Cross multiply
    642x = 885.54 × 421.14
  4. Step 4: Simplify right side
    642x = 372,936.32
  5. Step 5: Solve for x
    x = 372,936.32/642
  6. Step 6: Final answer
    x = 580.90

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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.