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Finding the Fourth Proportional to 800.78, 1,201.53 and 390.29

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Solution

The fourth proportional to 800.78, 1,201.53 and 390.29 is: 585.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    800.78 : 1,201.53 = 390.29 : x
  2. Step 2: Convert to fraction form
    800.78/1,201.53 = 390.29/x
  3. Step 3: Cross multiply
    800.78x = 1,201.53 × 390.29
  4. Step 4: Simplify right side
    800.78x = 468,945.14
  5. Step 5: Solve for x
    x = 468,945.14/800.78
  6. Step 6: Final answer
    x = 585.61

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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.