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Finding the Fourth Proportional to 139.99, 209.95 and 66.82

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Solution

The fourth proportional to 139.99, 209.95 and 66.82 is: 100.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    139.99 : 209.95 = 66.82 : x
  2. Step 2: Convert to fraction form
    139.99/209.95 = 66.82/x
  3. Step 3: Cross multiply
    139.99x = 209.95 × 66.82
  4. Step 4: Simplify right side
    139.99x = 14,028.86
  5. Step 5: Solve for x
    x = 14,028.86/139.99
  6. Step 6: Final answer
    x = 100.21

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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.