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Finding the Fourth Proportional to 678.78, 1,017.72 and 331.65

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Solution

The fourth proportional to 678.78, 1,017.72 and 331.65 is: 497.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.78 : 1,017.72 = 331.65 : x
  2. Step 2: Convert to fraction form
    678.78/1,017.72 = 331.65/x
  3. Step 3: Cross multiply
    678.78x = 1,017.72 × 331.65
  4. Step 4: Simplify right side
    678.78x = 337,526.84
  5. Step 5: Solve for x
    x = 337,526.84/678.78
  6. Step 6: Final answer
    x = 497.26

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.