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Finding the Fourth Proportional to 678.36, 935.90 and 398.49

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Solution

The fourth proportional to 678.36, 935.90 and 398.49 is: 549.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.36 : 935.90 = 398.49 : x
  2. Step 2: Convert to fraction form
    678.36/935.90 = 398.49/x
  3. Step 3: Cross multiply
    678.36x = 935.90 × 398.49
  4. Step 4: Simplify right side
    678.36x = 372,946.79
  5. Step 5: Solve for x
    x = 372,946.79/678.36
  6. Step 6: Final answer
    x = 549.78

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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.