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Finding the Fourth Proportional to 781.61, 1,078.49 and 501.75

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Solution

The fourth proportional to 781.61, 1,078.49 and 501.75 is: 692.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.61 : 1,078.49 = 501.75 : x
  2. Step 2: Convert to fraction form
    781.61/1,078.49 = 501.75/x
  3. Step 3: Cross multiply
    781.61x = 1,078.49 × 501.75
  4. Step 4: Simplify right side
    781.61x = 541,129.85
  5. Step 5: Solve for x
    x = 541,129.85/781.61
  6. Step 6: Final answer
    x = 692.33

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.