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Finding the Fourth Proportional to 781.77, 1,078.88 and 450.21

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Solution

The fourth proportional to 781.77, 1,078.88 and 450.21 is: 621.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    781.77 : 1,078.88 = 450.21 : x
  2. Step 2: Convert to fraction form
    781.77/1,078.88 = 450.21/x
  3. Step 3: Cross multiply
    781.77x = 1,078.88 × 450.21
  4. Step 4: Simplify right side
    781.77x = 485,722.56
  5. Step 5: Solve for x
    x = 485,722.56/781.77
  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.