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Finding the Fourth Proportional to 686.22, 946.91 and 406.40

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Solution

The fourth proportional to 686.22, 946.91 and 406.40 is: 560.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.22 : 946.91 = 406.40 : x
  2. Step 2: Convert to fraction form
    686.22/946.91 = 406.40/x
  3. Step 3: Cross multiply
    686.22x = 946.91 × 406.40
  4. Step 4: Simplify right side
    686.22x = 384,824.22
  5. Step 5: Solve for x
    x = 384,824.22/686.22
  6. Step 6: Final answer
    x = 560.79

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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.