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Finding the Fourth Proportional to 209.62, 314.43 and 128.31

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Solution

The fourth proportional to 209.62, 314.43 and 128.31 is: 192.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.62 : 314.43 = 128.31 : x
  2. Step 2: Convert to fraction form
    209.62/314.43 = 128.31/x
  3. Step 3: Cross multiply
    209.62x = 314.43 × 128.31
  4. Step 4: Simplify right side
    209.62x = 40,344.51
  5. Step 5: Solve for x
    x = 40,344.51/209.62
  6. Step 6: Final answer
    x = 192.47

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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.