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Finding the Fourth Proportional to 390.80, 539.31 and 216.17

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Solution

The fourth proportional to 390.80, 539.31 and 216.17 is: 298.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.80 : 539.31 = 216.17 : x
  2. Step 2: Convert to fraction form
    390.80/539.31 = 216.17/x
  3. Step 3: Cross multiply
    390.80x = 539.31 × 216.17
  4. Step 4: Simplify right side
    390.80x = 116,582.64
  5. Step 5: Solve for x
    x = 116,582.64/390.80
  6. Step 6: Final answer
    x = 298.32

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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.