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Finding the Fourth Proportional to 686.32, 1,028.76 and 339.76

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Solution

The fourth proportional to 686.32, 1,028.76 and 339.76 is: 509.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.32 : 1,028.76 = 339.76 : x
  2. Step 2: Convert to fraction form
    686.32/1,028.76 = 339.76/x
  3. Step 3: Cross multiply
    686.32x = 1,028.76 × 339.76
  4. Step 4: Simplify right side
    686.32x = 349,531.50
  5. Step 5: Solve for x
    x = 349,531.50/686.32
  6. Step 6: Final answer
    x = 509.28

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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.