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Finding the Fourth Proportional to 390.97, 539.55 and 216.31

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Solution

The fourth proportional to 390.97, 539.55 and 216.31 is: 298.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.97 : 539.55 = 216.31 : x
  2. Step 2: Convert to fraction form
    390.97/539.55 = 216.31/x
  3. Step 3: Cross multiply
    390.97x = 539.55 × 216.31
  4. Step 4: Simplify right side
    390.97x = 116,710.06
  5. Step 5: Solve for x
    x = 116,710.06/390.97
  6. Step 6: Final answer
    x = 298.51

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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.