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Finding the Fourth Proportional to 105.82, 145.98 and 81.28

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Solution

The fourth proportional to 105.82, 145.98 and 81.28 is: 112.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.82 : 145.98 = 81.28 : x
  2. Step 2: Convert to fraction form
    105.82/145.98 = 81.28/x
  3. Step 3: Cross multiply
    105.82x = 145.98 × 81.28
  4. Step 4: Simplify right side
    105.82x = 11,865.25
  5. Step 5: Solve for x
    x = 11,865.25/105.82
  6. Step 6: Final answer
    x = 112.13

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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.