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Finding the Fourth Proportional to 198.81, 274.16 and 128.89

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Solution

The fourth proportional to 198.81, 274.16 and 128.89 is: 177.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    198.81 : 274.16 = 128.89 : x
  2. Step 2: Convert to fraction form
    198.81/274.16 = 128.89/x
  3. Step 3: Cross multiply
    198.81x = 274.16 × 128.89
  4. Step 4: Simplify right side
    198.81x = 35,337.15
  5. Step 5: Solve for x
    x = 35,337.15/198.81
  6. Step 6: Final answer
    x = 177.74

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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.