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Finding the Fourth Proportional to 781, 1,171.50 and 203.88

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Solution

The fourth proportional to 781, 1,171.50 and 203.88 is: 305.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    781 : 1,171.50 = 203.88 : x
  2. Step 2: Convert to fraction form
    781/1,171.50 = 203.88/x
  3. Step 3: Cross multiply
    781x = 1,171.50 × 203.88
  4. Step 4: Simplify right side
    781x = 238,845.42
  5. Step 5: Solve for x
    x = 238,845.42/781
  6. Step 6: Final answer
    x = 305.82

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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.