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Finding the Fourth Proportional to 642.05, 885.83 and 393.31

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Solution

The fourth proportional to 642.05, 885.83 and 393.31 is: 542.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.05 : 885.83 = 393.31 : x
  2. Step 2: Convert to fraction form
    642.05/885.83 = 393.31/x
  3. Step 3: Cross multiply
    642.05x = 885.83 × 393.31
  4. Step 4: Simplify right side
    642.05x = 348,405.80
  5. Step 5: Solve for x
    x = 348,405.80/642.05
  6. Step 6: Final answer
    x = 542.65

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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.