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Finding the Fourth Proportional to 781.13, 1,078.05 and 501.26

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Solution

The fourth proportional to 781.13, 1,078.05 and 501.26 is: 691.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.13 : 1,078.05 = 501.26 : x
  2. Step 2: Convert to fraction form
    781.13/1,078.05 = 501.26/x
  3. Step 3: Cross multiply
    781.13x = 1,078.05 × 501.26
  4. Step 4: Simplify right side
    781.13x = 540,376.07
  5. Step 5: Solve for x
    x = 540,376.07/781.13
  6. Step 6: Final answer
    x = 691.79

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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.