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Finding the Fourth Proportional to 100.98, 139.31 and 66.05

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Solution

The fourth proportional to 100.98, 139.31 and 66.05 is: 91.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.98 : 139.31 = 66.05 : x
  2. Step 2: Convert to fraction form
    100.98/139.31 = 66.05/x
  3. Step 3: Cross multiply
    100.98x = 139.31 × 66.05
  4. Step 4: Simplify right side
    100.98x = 9,201.26
  5. Step 5: Solve for x
    x = 9,201.26/100.98
  6. Step 6: Final answer
    x = 91.12

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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.