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Finding the Fourth Proportional to 100, 149.39 and 81.88

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Solution

The fourth proportional to 100, 149.39 and 81.88 is: 122.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    100 : 149.39 = 81.88 : x
  2. Step 2: Convert to fraction form
    100/149.39 = 81.88/x
  3. Step 3: Cross multiply
    100x = 149.39 × 81.88
  4. Step 4: Simplify right side
    100x = 12,232.05
  5. Step 5: Solve for x
    x = 12,232.05/100
  6. Step 6: Final answer
    x = 122.32

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.