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Finding the Fourth Proportional to 686.48, 1,030.20 and 664.40

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Solution

The fourth proportional to 686.48, 1,030.20 and 664.40 is: 997.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.48 : 1,030.20 = 664.40 : x
  2. Step 2: Convert to fraction form
    686.48/1,030.20 = 664.40/x
  3. Step 3: Cross multiply
    686.48x = 1,030.20 × 664.40
  4. Step 4: Simplify right side
    686.48x = 684,464.88
  5. Step 5: Solve for x
    x = 684,464.88/686.48
  6. Step 6: Final answer
    x = 997.06

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.