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Finding the Fourth Proportional to 209.45, 312.12 and 195.78

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Solution

The fourth proportional to 209.45, 312.12 and 195.78 is: 291.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.45 : 312.12 = 195.78 : x
  2. Step 2: Convert to fraction form
    209.45/312.12 = 195.78/x
  3. Step 3: Cross multiply
    209.45x = 312.12 × 195.78
  4. Step 4: Simplify right side
    209.45x = 61,108.02
  5. Step 5: Solve for x
    x = 61,108.02/209.45
  6. Step 6: Final answer
    x = 291.75

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.