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Finding the Fourth Proportional to 678.47, 936.48 and 398.71

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Solution

The fourth proportional to 678.47, 936.48 and 398.71 is: 550.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.47 : 936.48 = 398.71 : x
  2. Step 2: Convert to fraction form
    678.47/936.48 = 398.71/x
  3. Step 3: Cross multiply
    678.47x = 936.48 × 398.71
  4. Step 4: Simplify right side
    678.47x = 373,383.94
  5. Step 5: Solve for x
    x = 373,383.94/678.47
  6. Step 6: Final answer
    x = 550.33

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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.