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Finding the Fourth Proportional to 1,287.90, 1,930.05 and 517.50

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Solution

The fourth proportional to 1,287.90, 1,930.05 and 517.50 is: 775.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,287.90 : 1,930.05 = 517.50 : x
  2. Step 2: Convert to fraction form
    1,287.90/1,930.05 = 517.50/x
  3. Step 3: Cross multiply
    1,287.90x = 1,930.05 × 517.50
  4. Step 4: Simplify right side
    1,287.90x = 998,800.88
  5. Step 5: Solve for x
    x = 998,800.88/1,287.90
  6. Step 6: Final answer
    x = 775.53

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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.