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Finding the Fourth Proportional to 138.58, 208.05 and 74.50

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Solution

The fourth proportional to 138.58, 208.05 and 74.50 is: 111.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.58 : 208.05 = 74.50 : x
  2. Step 2: Convert to fraction form
    138.58/208.05 = 74.50/x
  3. Step 3: Cross multiply
    138.58x = 208.05 × 74.50
  4. Step 4: Simplify right side
    138.58x = 15,499.73
  5. Step 5: Solve for x
    x = 15,499.73/138.58
  6. Step 6: Final answer
    x = 111.85

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.