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Finding the Fourth Proportional to 686.45, 1,023.78 and 613.55

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Solution

The fourth proportional to 686.45, 1,023.78 and 613.55 is: 915.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.45 : 1,023.78 = 613.55 : x
  2. Step 2: Convert to fraction form
    686.45/1,023.78 = 613.55/x
  3. Step 3: Cross multiply
    686.45x = 1,023.78 × 613.55
  4. Step 4: Simplify right side
    686.45x = 628,140.22
  5. Step 5: Solve for x
    x = 628,140.22/686.45
  6. Step 6: Final answer
    x = 915.06

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.