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Finding the Fourth Proportional to 105.70, 145.69 and 81.10

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Solution

The fourth proportional to 105.70, 145.69 and 81.10 is: 111.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.70 : 145.69 = 81.10 : x
  2. Step 2: Convert to fraction form
    105.70/145.69 = 81.10/x
  3. Step 3: Cross multiply
    105.70x = 145.69 × 81.10
  4. Step 4: Simplify right side
    105.70x = 11,815.46
  5. Step 5: Solve for x
    x = 11,815.46/105.70
  6. Step 6: Final answer
    x = 111.78

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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.