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Finding the Fourth Proportional to 686.80, 1,028.85 and 412.08

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Solution

The fourth proportional to 686.80, 1,028.85 and 412.08 is: 617.30

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.80 : 1,028.85 = 412.08 : x
  2. Step 2: Convert to fraction form
    686.80/1,028.85 = 412.08/x
  3. Step 3: Cross multiply
    686.80x = 1,028.85 × 412.08
  4. Step 4: Simplify right side
    686.80x = 423,963.36
  5. Step 5: Solve for x
    x = 423,963.36/686.80
  6. Step 6: Final answer
    x = 617.30

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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.