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Finding the Fourth Proportional to 100.97, 139.31 and 68.21

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Solution

The fourth proportional to 100.97, 139.31 and 68.21 is: 94.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.97 : 139.31 = 68.21 : x
  2. Step 2: Convert to fraction form
    100.97/139.31 = 68.21/x
  3. Step 3: Cross multiply
    100.97x = 139.31 × 68.21
  4. Step 4: Simplify right side
    100.97x = 9,501.30
  5. Step 5: Solve for x
    x = 9,501.30/100.97
  6. Step 6: Final answer
    x = 94.10

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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.