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Finding the Fourth Proportional to 212.20, 319.78 and 191.65

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Solution

The fourth proportional to 212.20, 319.78 and 191.65 is: 288.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.20 : 319.78 = 191.65 : x
  2. Step 2: Convert to fraction form
    212.20/319.78 = 191.65/x
  3. Step 3: Cross multiply
    212.20x = 319.78 × 191.65
  4. Step 4: Simplify right side
    212.20x = 61,285.84
  5. Step 5: Solve for x
    x = 61,285.84/212.20
  6. Step 6: Final answer
    x = 288.81

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.