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Finding the Fourth Proportional to 390.68, 539.35 and 285.66

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Solution

The fourth proportional to 390.68, 539.35 and 285.66 is: 394.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.68 : 539.35 = 285.66 : x
  2. Step 2: Convert to fraction form
    390.68/539.35 = 285.66/x
  3. Step 3: Cross multiply
    390.68x = 539.35 × 285.66
  4. Step 4: Simplify right side
    390.68x = 154,070.72
  5. Step 5: Solve for x
    x = 154,070.72/390.68
  6. Step 6: Final answer
    x = 394.37

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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.