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Finding the Fourth Proportional to 139.06, 208.47 and 66.82

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Solution

The fourth proportional to 139.06, 208.47 and 66.82 is: 100.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.06 : 208.47 = 66.82 : x
  2. Step 2: Convert to fraction form
    139.06/208.47 = 66.82/x
  3. Step 3: Cross multiply
    139.06x = 208.47 × 66.82
  4. Step 4: Simplify right side
    139.06x = 13,929.97
  5. Step 5: Solve for x
    x = 13,929.97/139.06
  6. Step 6: Final answer
    x = 100.17

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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.