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Finding the Fourth Proportional to 390.31, 585.09 and 146.78

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Solution

The fourth proportional to 390.31, 585.09 and 146.78 is: 220.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.31 : 585.09 = 146.78 : x
  2. Step 2: Convert to fraction form
    390.31/585.09 = 146.78/x
  3. Step 3: Cross multiply
    390.31x = 585.09 × 146.78
  4. Step 4: Simplify right side
    390.31x = 85,879.51
  5. Step 5: Solve for x
    x = 85,879.51/390.31
  6. Step 6: Final answer
    x = 220.03

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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.