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Finding the Fourth Proportional to 678.61, 936.71 and 398.84

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Solution

The fourth proportional to 678.61, 936.71 and 398.84 is: 550.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.61 : 936.71 = 398.84 : x
  2. Step 2: Convert to fraction form
    678.61/936.71 = 398.84/x
  3. Step 3: Cross multiply
    678.61x = 936.71 × 398.84
  4. Step 4: Simplify right side
    678.61x = 373,594.25
  5. Step 5: Solve for x
    x = 373,594.25/678.61
  6. Step 6: Final answer
    x = 550.53

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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.