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Finding the Fourth Proportional to 101.22, 139.58 and 76.72

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Solution

The fourth proportional to 101.22, 139.58 and 76.72 is: 105.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.22 : 139.58 = 76.72 : x
  2. Step 2: Convert to fraction form
    101.22/139.58 = 76.72/x
  3. Step 3: Cross multiply
    101.22x = 139.58 × 76.72
  4. Step 4: Simplify right side
    101.22x = 10,707.88
  5. Step 5: Solve for x
    x = 10,707.88/101.22
  6. Step 6: Final answer
    x = 105.79

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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.