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Finding the Fourth Proportional to 128.81, 193.19 and 47.60

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Solution

The fourth proportional to 128.81, 193.19 and 47.60 is: 71.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.81 : 193.19 = 47.60 : x
  2. Step 2: Convert to fraction form
    128.81/193.19 = 47.60/x
  3. Step 3: Cross multiply
    128.81x = 193.19 × 47.60
  4. Step 4: Simplify right side
    128.81x = 9,194.64
  5. Step 5: Solve for x
    x = 9,194.64/128.81
  6. Step 6: Final answer
    x = 71.38

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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.