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Finding the Fourth Proportional to 390.54, 538.38 and 331.29

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Solution

The fourth proportional to 390.54, 538.38 and 331.29 is: 456.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.54 : 538.38 = 331.29 : x
  2. Step 2: Convert to fraction form
    390.54/538.38 = 331.29/x
  3. Step 3: Cross multiply
    390.54x = 538.38 × 331.29
  4. Step 4: Simplify right side
    390.54x = 178,359.91
  5. Step 5: Solve for x
    x = 178,359.91/390.54
  6. Step 6: Final answer
    x = 456.70

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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.