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Finding the Fourth Proportional to 781.67, 1,078.20 and 501.46

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Solution

The fourth proportional to 781.67, 1,078.20 and 501.46 is: 691.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.67 : 1,078.20 = 501.46 : x
  2. Step 2: Convert to fraction form
    781.67/1,078.20 = 501.46/x
  3. Step 3: Cross multiply
    781.67x = 1,078.20 × 501.46
  4. Step 4: Simplify right side
    781.67x = 540,671.66
  5. Step 5: Solve for x
    x = 540,671.66/781.67
  6. Step 6: Final answer
    x = 691.69

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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.