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Finding the Fourth Proportional to 89.70, 123.08 and 81.48

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Solution

The fourth proportional to 89.70, 123.08 and 81.48 is: 111.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.70 : 123.08 = 81.48 : x
  2. Step 2: Convert to fraction form
    89.70/123.08 = 81.48/x
  3. Step 3: Cross multiply
    89.70x = 123.08 × 81.48
  4. Step 4: Simplify right side
    89.70x = 10,028.56
  5. Step 5: Solve for x
    x = 10,028.56/89.70
  6. Step 6: Final answer
    x = 111.80

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.