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Finding the Fourth Proportional to 89.91, 134.89 and 28.21

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Solution

The fourth proportional to 89.91, 134.89 and 28.21 is: 42.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.91 : 134.89 = 28.21 : x
  2. Step 2: Convert to fraction form
    89.91/134.89 = 28.21/x
  3. Step 3: Cross multiply
    89.91x = 134.89 × 28.21
  4. Step 4: Simplify right side
    89.91x = 3,805.25
  5. Step 5: Solve for x
    x = 3,805.25/89.91
  6. Step 6: Final answer
    x = 42.32

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.