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Finding the Fourth Proportional to 138.78, 208.25 and 98.46

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Solution

The fourth proportional to 138.78, 208.25 and 98.46 is: 147.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.78 : 208.25 = 98.46 : x
  2. Step 2: Convert to fraction form
    138.78/208.25 = 98.46/x
  3. Step 3: Cross multiply
    138.78x = 208.25 × 98.46
  4. Step 4: Simplify right side
    138.78x = 20,503.80
  5. Step 5: Solve for x
    x = 20,503.80/138.78
  6. Step 6: Final answer
    x = 147.74

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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.