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Finding the Fourth Proportional to 686.16, 1,029.60 and 398.16

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Solution

The fourth proportional to 686.16, 1,029.60 and 398.16 is: 597.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.16 : 1,029.60 = 398.16 : x
  2. Step 2: Convert to fraction form
    686.16/1,029.60 = 398.16/x
  3. Step 3: Cross multiply
    686.16x = 1,029.60 × 398.16
  4. Step 4: Simplify right side
    686.16x = 409,945.54
  5. Step 5: Solve for x
    x = 409,945.54/686.16
  6. Step 6: Final answer
    x = 597.45

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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.