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Finding the Fourth Proportional to 642.39, 886.31 and 393.46

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Solution

The fourth proportional to 642.39, 886.31 and 393.46 is: 542.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.39 : 886.31 = 393.46 : x
  2. Step 2: Convert to fraction form
    642.39/886.31 = 393.46/x
  3. Step 3: Cross multiply
    642.39x = 886.31 × 393.46
  4. Step 4: Simplify right side
    642.39x = 348,727.53
  5. Step 5: Solve for x
    x = 348,727.53/642.39
  6. Step 6: Final answer
    x = 542.86

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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.