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Finding the Fourth Proportional to 105.39, 145.71 and 80.91

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Solution

The fourth proportional to 105.39, 145.71 and 80.91 is: 111.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.39 : 145.71 = 80.91 : x
  2. Step 2: Convert to fraction form
    105.39/145.71 = 80.91/x
  3. Step 3: Cross multiply
    105.39x = 145.71 × 80.91
  4. Step 4: Simplify right side
    105.39x = 11,789.40
  5. Step 5: Solve for x
    x = 11,789.40/105.39
  6. Step 6: Final answer
    x = 111.86

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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.