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Finding the Fourth Proportional to 691.78, 1,037.68 and 385.58

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Solution

The fourth proportional to 691.78, 1,037.68 and 385.58 is: 578.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    691.78 : 1,037.68 = 385.58 : x
  2. Step 2: Convert to fraction form
    691.78/1,037.68 = 385.58/x
  3. Step 3: Cross multiply
    691.78x = 1,037.68 × 385.58
  4. Step 4: Simplify right side
    691.78x = 400,110.86
  5. Step 5: Solve for x
    x = 400,110.86/691.78
  6. Step 6: Final answer
    x = 578.38

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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.