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Finding the Fourth Proportional to 209.45, 314.31 and 128.27

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Solution

The fourth proportional to 209.45, 314.31 and 128.27 is: 192.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.45 : 314.31 = 128.27 : x
  2. Step 2: Convert to fraction form
    209.45/314.31 = 128.27/x
  3. Step 3: Cross multiply
    209.45x = 314.31 × 128.27
  4. Step 4: Simplify right side
    209.45x = 40,316.54
  5. Step 5: Solve for x
    x = 40,316.54/209.45
  6. Step 6: Final answer
    x = 192.49

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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.