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Finding the Fourth Proportional to 209.85, 314.78 and 72.89

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Solution

The fourth proportional to 209.85, 314.78 and 72.89 is: 109.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.85 : 314.78 = 72.89 : x
  2. Step 2: Convert to fraction form
    209.85/314.78 = 72.89/x
  3. Step 3: Cross multiply
    209.85x = 314.78 × 72.89
  4. Step 4: Simplify right side
    209.85x = 22,942.38
  5. Step 5: Solve for x
    x = 22,942.38/209.85
  6. Step 6: Final answer
    x = 109.33

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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.