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Finding the Fourth Proportional to 89.78, 123.73 and 81.35

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Solution

The fourth proportional to 89.78, 123.73 and 81.35 is: 112.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.78 : 123.73 = 81.35 : x
  2. Step 2: Convert to fraction form
    89.78/123.73 = 81.35/x
  3. Step 3: Cross multiply
    89.78x = 123.73 × 81.35
  4. Step 4: Simplify right side
    89.78x = 10,065.44
  5. Step 5: Solve for x
    x = 10,065.44/89.78
  6. Step 6: Final answer
    x = 112.11

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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.