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Finding the Fourth Proportional to 781.22, 1,078.15 and 449.74

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Solution

The fourth proportional to 781.22, 1,078.15 and 449.74 is: 620.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.22 : 1,078.15 = 449.74 : x
  2. Step 2: Convert to fraction form
    781.22/1,078.15 = 449.74/x
  3. Step 3: Cross multiply
    781.22x = 1,078.15 × 449.74
  4. Step 4: Simplify right side
    781.22x = 484,887.18
  5. Step 5: Solve for x
    x = 484,887.18/781.22
  6. Step 6: Final answer
    x = 620.68

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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.