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Finding the Fourth Proportional to 390.82, 539.43 and 257.98

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Solution

The fourth proportional to 390.82, 539.43 and 257.98 is: 356.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.82 : 539.43 = 257.98 : x
  2. Step 2: Convert to fraction form
    390.82/539.43 = 257.98/x
  3. Step 3: Cross multiply
    390.82x = 539.43 × 257.98
  4. Step 4: Simplify right side
    390.82x = 139,162.15
  5. Step 5: Solve for x
    x = 139,162.15/390.82
  6. Step 6: Final answer
    x = 356.08

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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.