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Finding the Fourth Proportional to 678.44, 1,016.70 and 389.28

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Solution

The fourth proportional to 678.44, 1,016.70 and 389.28 is: 583.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.44 : 1,016.70 = 389.28 : x
  2. Step 2: Convert to fraction form
    678.44/1,016.70 = 389.28/x
  3. Step 3: Cross multiply
    678.44x = 1,016.70 × 389.28
  4. Step 4: Simplify right side
    678.44x = 395,780.98
  5. Step 5: Solve for x
    x = 395,780.98/678.44
  6. Step 6: Final answer
    x = 583.37

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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.