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Finding the Fourth Proportional to 842.78, 1,264.98 and 789.72

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Solution

The fourth proportional to 842.78, 1,264.98 and 789.72 is: 1,185.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    842.78 : 1,264.98 = 789.72 : x
  2. Step 2: Convert to fraction form
    842.78/1,264.98 = 789.72/x
  3. Step 3: Cross multiply
    842.78x = 1,264.98 × 789.72
  4. Step 4: Simplify right side
    842.78x = 998,980.01
  5. Step 5: Solve for x
    x = 998,980.01/842.78
  6. Step 6: Final answer
    x = 1,185.34

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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.