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Finding the Fourth Proportional to 128.76, 193.12 and 98.38

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Solution

The fourth proportional to 128.76, 193.12 and 98.38 is: 147.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.76 : 193.12 = 98.38 : x
  2. Step 2: Convert to fraction form
    128.76/193.12 = 98.38/x
  3. Step 3: Cross multiply
    128.76x = 193.12 × 98.38
  4. Step 4: Simplify right side
    128.76x = 18,999.15
  5. Step 5: Solve for x
    x = 18,999.15/128.76
  6. Step 6: Final answer
    x = 147.55

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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.