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Finding the Fourth Proportional to 100.98, 139.32 and 80.19

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Solution

The fourth proportional to 100.98, 139.32 and 80.19 is: 110.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.98 : 139.32 = 80.19 : x
  2. Step 2: Convert to fraction form
    100.98/139.32 = 80.19/x
  3. Step 3: Cross multiply
    100.98x = 139.32 × 80.19
  4. Step 4: Simplify right side
    100.98x = 11,172.07
  5. Step 5: Solve for x
    x = 11,172.07/100.98
  6. Step 6: Final answer
    x = 110.64

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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.