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Finding the Fourth Proportional to 89.78, 134.06 and 69.39

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Solution

The fourth proportional to 89.78, 134.06 and 69.39 is: 103.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.78 : 134.06 = 69.39 : x
  2. Step 2: Convert to fraction form
    89.78/134.06 = 69.39/x
  3. Step 3: Cross multiply
    89.78x = 134.06 × 69.39
  4. Step 4: Simplify right side
    89.78x = 9,302.08
  5. Step 5: Solve for x
    x = 9,302.08/89.78
  6. Step 6: Final answer
    x = 103.62

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.