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Finding the Fourth Proportional to 101.12, 139.44 and 81.68

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Solution

The fourth proportional to 101.12, 139.44 and 81.68 is: 112.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.12 : 139.44 = 81.68 : x
  2. Step 2: Convert to fraction form
    101.12/139.44 = 81.68/x
  3. Step 3: Cross multiply
    101.12x = 139.44 × 81.68
  4. Step 4: Simplify right side
    101.12x = 11,389.46
  5. Step 5: Solve for x
    x = 11,389.46/101.12
  6. Step 6: Final answer
    x = 112.63

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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.