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Finding the Fourth Proportional to 100.97, 139.58 and 80.39

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Solution

The fourth proportional to 100.97, 139.58 and 80.39 is: 111.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.97 : 139.58 = 80.39 : x
  2. Step 2: Convert to fraction form
    100.97/139.58 = 80.39/x
  3. Step 3: Cross multiply
    100.97x = 139.58 × 80.39
  4. Step 4: Simplify right side
    100.97x = 11,220.84
  5. Step 5: Solve for x
    x = 11,220.84/100.97
  6. Step 6: Final answer
    x = 111.13

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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.