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Finding the Fourth Proportional to 1,286.70, 1,930.05 and 312.81

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Solution

The fourth proportional to 1,286.70, 1,930.05 and 312.81 is: 469.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,286.70 : 1,930.05 = 312.81 : x
  2. Step 2: Convert to fraction form
    1,286.70/1,930.05 = 312.81/x
  3. Step 3: Cross multiply
    1,286.70x = 1,930.05 × 312.81
  4. Step 4: Simplify right side
    1,286.70x = 603,738.94
  5. Step 5: Solve for x
    x = 603,738.94/1,286.70
  6. Step 6: Final answer
    x = 469.22

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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.