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Finding the Fourth Proportional to 212.94, 319.41 and 84.78

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Solution

The fourth proportional to 212.94, 319.41 and 84.78 is: 127.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    212.94 : 319.41 = 84.78 : x
  2. Step 2: Convert to fraction form
    212.94/319.41 = 84.78/x
  3. Step 3: Cross multiply
    212.94x = 319.41 × 84.78
  4. Step 4: Simplify right side
    212.94x = 27,078.57
  5. Step 5: Solve for x
    x = 27,078.57/212.94
  6. Step 6: Final answer
    x = 127.17

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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.