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Finding the Fourth Proportional to 390.45, 539.01 and 257.82

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Solution

The fourth proportional to 390.45, 539.01 and 257.82 is: 355.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.45 : 539.01 = 257.82 : x
  2. Step 2: Convert to fraction form
    390.45/539.01 = 257.82/x
  3. Step 3: Cross multiply
    390.45x = 539.01 × 257.82
  4. Step 4: Simplify right side
    390.45x = 138,967.56
  5. Step 5: Solve for x
    x = 138,967.56/390.45
  6. Step 6: Final answer
    x = 355.92

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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.