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Finding the Fourth Proportional to 686.05, 1,028.40 and 613.15

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Solution

The fourth proportional to 686.05, 1,028.40 and 613.15 is: 919.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.05 : 1,028.40 = 613.15 : x
  2. Step 2: Convert to fraction form
    686.05/1,028.40 = 613.15/x
  3. Step 3: Cross multiply
    686.05x = 1,028.40 × 613.15
  4. Step 4: Simplify right side
    686.05x = 630,563.46
  5. Step 5: Solve for x
    x = 630,563.46/686.05
  6. Step 6: Final answer
    x = 919.12

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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.