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Finding the Fourth Proportional to 686.66, 1,029.99 and 378.45

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Solution

The fourth proportional to 686.66, 1,029.99 and 378.45 is: 567.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    686.66 : 1,029.99 = 378.45 : x
  2. Step 2: Convert to fraction form
    686.66/1,029.99 = 378.45/x
  3. Step 3: Cross multiply
    686.66x = 1,029.99 × 378.45
  4. Step 4: Simplify right side
    686.66x = 389,801.13
  5. Step 5: Solve for x
    x = 389,801.13/686.66
  6. Step 6: Final answer
    x = 567.68

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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.