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Finding the Fourth Proportional to 642.57, 885.87 and 406.40

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Solution

The fourth proportional to 642.57, 885.87 and 406.40 is: 560.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    642.57 : 885.87 = 406.40 : x
  2. Step 2: Convert to fraction form
    642.57/885.87 = 406.40/x
  3. Step 3: Cross multiply
    642.57x = 885.87 × 406.40
  4. Step 4: Simplify right side
    642.57x = 360,015.54
  5. Step 5: Solve for x
    x = 360,015.54/642.57
  6. Step 6: Final answer
    x = 560.27

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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.