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Finding the Fourth Proportional to 216.14, 298.31 and 128.81

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Solution

The fourth proportional to 216.14, 298.31 and 128.81 is: 177.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    216.14 : 298.31 = 128.81 : x
  2. Step 2: Convert to fraction form
    216.14/298.31 = 128.81/x
  3. Step 3: Cross multiply
    216.14x = 298.31 × 128.81
  4. Step 4: Simplify right side
    216.14x = 38,425.41
  5. Step 5: Solve for x
    x = 38,425.41/216.14
  6. Step 6: Final answer
    x = 177.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.