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Finding the Fourth Proportional to 209.94, 315.11 and 128.94

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Solution

The fourth proportional to 209.94, 315.11 and 128.94 is: 193.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.94 : 315.11 = 128.94 : x
  2. Step 2: Convert to fraction form
    209.94/315.11 = 128.94/x
  3. Step 3: Cross multiply
    209.94x = 315.11 × 128.94
  4. Step 4: Simplify right side
    209.94x = 40,630.61
  5. Step 5: Solve for x
    x = 40,630.61/209.94
  6. Step 6: Final answer
    x = 193.53

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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.