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Finding the Fourth Proportional to 390.91, 539.43 and 216.25

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Solution

The fourth proportional to 390.91, 539.43 and 216.25 is: 298.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.91 : 539.43 = 216.25 : x
  2. Step 2: Convert to fraction form
    390.91/539.43 = 216.25/x
  3. Step 3: Cross multiply
    390.91x = 539.43 × 216.25
  4. Step 4: Simplify right side
    390.91x = 116,651.74
  5. Step 5: Solve for x
    x = 116,651.74/390.91
  6. Step 6: Final answer
    x = 298.41

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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.