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Finding the Fourth Proportional to 209.98, 315.06 and 128.62

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Solution

The fourth proportional to 209.98, 315.06 and 128.62 is: 192.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.98 : 315.06 = 128.62 : x
  2. Step 2: Convert to fraction form
    209.98/315.06 = 128.62/x
  3. Step 3: Cross multiply
    209.98x = 315.06 × 128.62
  4. Step 4: Simplify right side
    209.98x = 40,523.02
  5. Step 5: Solve for x
    x = 40,523.02/209.98
  6. Step 6: Final answer
    x = 192.99

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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.