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Finding the Fourth Proportional to 678.69, 936.59 and 398.92

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Solution

The fourth proportional to 678.69, 936.59 and 398.92 is: 550.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.69 : 936.59 = 398.92 : x
  2. Step 2: Convert to fraction form
    678.69/936.59 = 398.92/x
  3. Step 3: Cross multiply
    678.69x = 936.59 × 398.92
  4. Step 4: Simplify right side
    678.69x = 373,624.48
  5. Step 5: Solve for x
    x = 373,624.48/678.69
  6. Step 6: Final answer
    x = 550.51

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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.