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Finding the Fourth Proportional to 686.55, 1,029.15 and 613.65

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Solution

The fourth proportional to 686.55, 1,029.15 and 613.65 is: 919.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.55 : 1,029.15 = 613.65 : x
  2. Step 2: Convert to fraction form
    686.55/1,029.15 = 613.65/x
  3. Step 3: Cross multiply
    686.55x = 1,029.15 × 613.65
  4. Step 4: Simplify right side
    686.55x = 631,537.90
  5. Step 5: Solve for x
    x = 631,537.90/686.55
  6. Step 6: Final answer
    x = 919.87

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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.