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Finding the Fourth Proportional to 678.17, 935.66 and 398.42

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Solution

The fourth proportional to 678.17, 935.66 and 398.42 is: 549.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.17 : 935.66 = 398.42 : x
  2. Step 2: Convert to fraction form
    678.17/935.66 = 398.42/x
  3. Step 3: Cross multiply
    678.17x = 935.66 × 398.42
  4. Step 4: Simplify right side
    678.17x = 372,778.99
  5. Step 5: Solve for x
    x = 372,778.99/678.17
  6. Step 6: Final answer
    x = 549.69

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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.