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Finding the Fourth Proportional to 390.92, 539.47 and 213.88

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Solution

The fourth proportional to 390.92, 539.47 and 213.88 is: 295.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.92 : 539.47 = 213.88 : x
  2. Step 2: Convert to fraction form
    390.92/539.47 = 213.88/x
  3. Step 3: Cross multiply
    390.92x = 539.47 × 213.88
  4. Step 4: Simplify right side
    390.92x = 115,381.84
  5. Step 5: Solve for x
    x = 115,381.84/390.92
  6. Step 6: Final answer
    x = 295.15

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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.