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Finding the Fourth Proportional to 686.32, 946.94 and 420.90

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Solution

The fourth proportional to 686.32, 946.94 and 420.90 is: 580.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.32 : 946.94 = 420.90 : x
  2. Step 2: Convert to fraction form
    686.32/946.94 = 420.90/x
  3. Step 3: Cross multiply
    686.32x = 946.94 × 420.90
  4. Step 4: Simplify right side
    686.32x = 398,567.05
  5. Step 5: Solve for x
    x = 398,567.05/686.32
  6. Step 6: Final answer
    x = 580.73

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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.