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Finding the Fourth Proportional to 781.75, 1,078.86 and 450.21

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Solution

The fourth proportional to 781.75, 1,078.86 and 450.21 is: 621.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.75 : 1,078.86 = 450.21 : x
  2. Step 2: Convert to fraction form
    781.75/1,078.86 = 450.21/x
  3. Step 3: Cross multiply
    781.75x = 1,078.86 × 450.21
  4. Step 4: Simplify right side
    781.75x = 485,705.92
  5. Step 5: Solve for x
    x = 485,705.92/781.75
  6. Step 6: Final answer
    x = 621.31

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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.