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Finding the Fourth Proportional to 801.78, 1,201.48 and 405.90

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Solution

The fourth proportional to 801.78, 1,201.48 and 405.90 is: 608.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    801.78 : 1,201.48 = 405.90 : x
  2. Step 2: Convert to fraction form
    801.78/1,201.48 = 405.90/x
  3. Step 3: Cross multiply
    801.78x = 1,201.48 × 405.90
  4. Step 4: Simplify right side
    801.78x = 487,680.73
  5. Step 5: Solve for x
    x = 487,680.73/801.78
  6. Step 6: Final answer
    x = 608.25

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.