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Finding the Fourth Proportional to 139.45, 209.06 and 66.38

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Solution

The fourth proportional to 139.45, 209.06 and 66.38 is: 99.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.45 : 209.06 = 66.38 : x
  2. Step 2: Convert to fraction form
    139.45/209.06 = 66.38/x
  3. Step 3: Cross multiply
    139.45x = 209.06 × 66.38
  4. Step 4: Simplify right side
    139.45x = 13,876.36
  5. Step 5: Solve for x
    x = 13,876.36/139.45
  6. Step 6: Final answer
    x = 99.51

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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.