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Finding the Fourth Proportional to 678.14, 936 and 398.36

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Solution

The fourth proportional to 678.14, 936 and 398.36 is: 549.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.14 : 936 = 398.36 : x
  2. Step 2: Convert to fraction form
    678.14/936 = 398.36/x
  3. Step 3: Cross multiply
    678.14x = 936 × 398.36
  4. Step 4: Simplify right side
    678.14x = 372,864.96
  5. Step 5: Solve for x
    x = 372,864.96/678.14
  6. Step 6: Final answer
    x = 549.83

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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.