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Finding the Fourth Proportional to 100.75, 139.04 and 71.30

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Solution

The fourth proportional to 100.75, 139.04 and 71.30 is: 98.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    100.75 : 139.04 = 71.30 : x
  2. Step 2: Convert to fraction form
    100.75/139.04 = 71.30/x
  3. Step 3: Cross multiply
    100.75x = 139.04 × 71.30
  4. Step 4: Simplify right side
    100.75x = 9,912.63
  5. Step 5: Solve for x
    x = 9,912.63/100.75
  6. Step 6: Final answer
    x = 98.39

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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.