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Finding the Fourth Proportional to 140.06, 209.82 and 85.70

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Solution

The fourth proportional to 140.06, 209.82 and 85.70 is: 128.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    140.06 : 209.82 = 85.70 : x
  2. Step 2: Convert to fraction form
    140.06/209.82 = 85.70/x
  3. Step 3: Cross multiply
    140.06x = 209.82 × 85.70
  4. Step 4: Simplify right side
    140.06x = 17,981.57
  5. Step 5: Solve for x
    x = 17,981.57/140.06
  6. Step 6: Final answer
    x = 128.38

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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.