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Finding the Fourth Proportional to 642, 885.87 and 393.36

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Solution

The fourth proportional to 642, 885.87 and 393.36 is: 542.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    642 : 885.87 = 393.36 : x
  2. Step 2: Convert to fraction form
    642/885.87 = 393.36/x
  3. Step 3: Cross multiply
    642x = 885.87 × 393.36
  4. Step 4: Simplify right side
    642x = 348,465.82
  5. Step 5: Solve for x
    x = 348,465.82/642
  6. Step 6: Final answer
    x = 542.78

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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.