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Finding the Fourth Proportional to 390.95, 539.52 and 213.91

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Solution

The fourth proportional to 390.95, 539.52 and 213.91 is: 295.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.95 : 539.52 = 213.91 : x
  2. Step 2: Convert to fraction form
    390.95/539.52 = 213.91/x
  3. Step 3: Cross multiply
    390.95x = 539.52 × 213.91
  4. Step 4: Simplify right side
    390.95x = 115,408.72
  5. Step 5: Solve for x
    x = 115,408.72/390.95
  6. Step 6: Final answer
    x = 295.20

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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.