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Finding the Fourth Proportional to 781.66, 1,078.95 and 519.63

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Solution

The fourth proportional to 781.66, 1,078.95 and 519.63 is: 717.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.66 : 1,078.95 = 519.63 : x
  2. Step 2: Convert to fraction form
    781.66/1,078.95 = 519.63/x
  3. Step 3: Cross multiply
    781.66x = 1,078.95 × 519.63
  4. Step 4: Simplify right side
    781.66x = 560,654.79
  5. Step 5: Solve for x
    x = 560,654.79/781.66
  6. Step 6: Final answer
    x = 717.26

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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.