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Finding the Fourth Proportional to 1,286.75, 1,930.13 and 312.85

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Solution

The fourth proportional to 1,286.75, 1,930.13 and 312.85 is: 469.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.75 : 1,930.13 = 312.85 : x
  2. Step 2: Convert to fraction form
    1,286.75/1,930.13 = 312.85/x
  3. Step 3: Cross multiply
    1,286.75x = 1,930.13 × 312.85
  4. Step 4: Simplify right side
    1,286.75x = 603,843.19
  5. Step 5: Solve for x
    x = 603,843.19/1,286.75
  6. Step 6: Final answer
    x = 469.28

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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.