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Finding the Fourth Proportional to 101.12, 139.60 and 76.64

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Solution

The fourth proportional to 101.12, 139.60 and 76.64 is: 105.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.12 : 139.60 = 76.64 : x
  2. Step 2: Convert to fraction form
    101.12/139.60 = 76.64/x
  3. Step 3: Cross multiply
    101.12x = 139.60 × 76.64
  4. Step 4: Simplify right side
    101.12x = 10,698.94
  5. Step 5: Solve for x
    x = 10,698.94/101.12
  6. Step 6: Final answer
    x = 105.80

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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.