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Finding the Fourth Proportional to 138.95, 208.34 and 70.39

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Solution

The fourth proportional to 138.95, 208.34 and 70.39 is: 105.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.95 : 208.34 = 70.39 : x
  2. Step 2: Convert to fraction form
    138.95/208.34 = 70.39/x
  3. Step 3: Cross multiply
    138.95x = 208.34 × 70.39
  4. Step 4: Simplify right side
    138.95x = 14,665.05
  5. Step 5: Solve for x
    x = 14,665.05/138.95
  6. Step 6: Final answer
    x = 105.54

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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.