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Finding the Fourth Proportional to 678.36, 1,016.82 and 642.36

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Solution

The fourth proportional to 678.36, 1,016.82 and 642.36 is: 962.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.36 : 1,016.82 = 642.36 : x
  2. Step 2: Convert to fraction form
    678.36/1,016.82 = 642.36/x
  3. Step 3: Cross multiply
    678.36x = 1,016.82 × 642.36
  4. Step 4: Simplify right side
    678.36x = 653,164.50
  5. Step 5: Solve for x
    x = 653,164.50/678.36
  6. Step 6: Final answer
    x = 962.86

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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.