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Finding the Fourth Proportional to 439.94, 659.90 and 257.20

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Solution

The fourth proportional to 439.94, 659.90 and 257.20 is: 385.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    439.94 : 659.90 = 257.20 : x
  2. Step 2: Convert to fraction form
    439.94/659.90 = 257.20/x
  3. Step 3: Cross multiply
    439.94x = 659.90 × 257.20
  4. Step 4: Simplify right side
    439.94x = 169,721.69
  5. Step 5: Solve for x
    x = 169,721.69/439.94
  6. Step 6: Final answer
    x = 385.78

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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.