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Finding the Fourth Proportional to 678.29, 935.98 and 398.65

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Solution

The fourth proportional to 678.29, 935.98 and 398.65 is: 550.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.29 : 935.98 = 398.65 : x
  2. Step 2: Convert to fraction form
    678.29/935.98 = 398.65/x
  3. Step 3: Cross multiply
    678.29x = 935.98 × 398.65
  4. Step 4: Simplify right side
    678.29x = 373,128.43
  5. Step 5: Solve for x
    x = 373,128.43/678.29
  6. Step 6: Final answer
    x = 550.10

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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.