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Finding the Fourth Proportional to 759.78, 1,139.67 and 515.70

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Solution

The fourth proportional to 759.78, 1,139.67 and 515.70 is: 773.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    759.78 : 1,139.67 = 515.70 : x
  2. Step 2: Convert to fraction form
    759.78/1,139.67 = 515.70/x
  3. Step 3: Cross multiply
    759.78x = 1,139.67 × 515.70
  4. Step 4: Simplify right side
    759.78x = 587,727.82
  5. Step 5: Solve for x
    x = 587,727.82/759.78
  6. Step 6: Final answer
    x = 773.55

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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.