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Finding the Fourth Proportional to 138.82, 208.36 and 70.39

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Solution

The fourth proportional to 138.82, 208.36 and 70.39 is: 105.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    138.82 : 208.36 = 70.39 : x
  2. Step 2: Convert to fraction form
    138.82/208.36 = 70.39/x
  3. Step 3: Cross multiply
    138.82x = 208.36 × 70.39
  4. Step 4: Simplify right side
    138.82x = 14,666.46
  5. Step 5: Solve for x
    x = 14,666.46/138.82
  6. Step 6: Final answer
    x = 105.65

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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.