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Finding the Fourth Proportional to 89.64, 123.54 and 81.42

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Solution

The fourth proportional to 89.64, 123.54 and 81.42 is: 112.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.64 : 123.54 = 81.42 : x
  2. Step 2: Convert to fraction form
    89.64/123.54 = 81.42/x
  3. Step 3: Cross multiply
    89.64x = 123.54 × 81.42
  4. Step 4: Simplify right side
    89.64x = 10,058.63
  5. Step 5: Solve for x
    x = 10,058.63/89.64
  6. Step 6: Final answer
    x = 112.21

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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.