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Finding the Fourth Proportional to 89.75, 123.45 and 78.82

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Solution

The fourth proportional to 89.75, 123.45 and 78.82 is: 108.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.75 : 123.45 = 78.82 : x
  2. Step 2: Convert to fraction form
    89.75/123.45 = 78.82/x
  3. Step 3: Cross multiply
    89.75x = 123.45 × 78.82
  4. Step 4: Simplify right side
    89.75x = 9,730.33
  5. Step 5: Solve for x
    x = 9,730.33/89.75
  6. Step 6: Final answer
    x = 108.42

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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.