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Finding the Fourth Proportional to 100.98, 139.42 and 80.30

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Solution

The fourth proportional to 100.98, 139.42 and 80.30 is: 110.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.98 : 139.42 = 80.30 : x
  2. Step 2: Convert to fraction form
    100.98/139.42 = 80.30/x
  3. Step 3: Cross multiply
    100.98x = 139.42 × 80.30
  4. Step 4: Simplify right side
    100.98x = 11,196.07
  5. Step 5: Solve for x
    x = 11,196.07/100.98
  6. Step 6: Final answer
    x = 110.88

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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.