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Finding the Fourth Proportional to 101.69, 139.95 and 80.90

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Solution

The fourth proportional to 101.69, 139.95 and 80.90 is: 111.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    101.69 : 139.95 = 80.90 : x
  2. Step 2: Convert to fraction form
    101.69/139.95 = 80.90/x
  3. Step 3: Cross multiply
    101.69x = 139.95 × 80.90
  4. Step 4: Simplify right side
    101.69x = 11,321.26
  5. Step 5: Solve for x
    x = 11,321.26/101.69
  6. Step 6: Final answer
    x = 111.34

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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.