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Finding the Fourth Proportional to 128.85, 193.34 and 47.71

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Solution

The fourth proportional to 128.85, 193.34 and 47.71 is: 71.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.85 : 193.34 = 47.71 : x
  2. Step 2: Convert to fraction form
    128.85/193.34 = 47.71/x
  3. Step 3: Cross multiply
    128.85x = 193.34 × 47.71
  4. Step 4: Simplify right side
    128.85x = 9,224.25
  5. Step 5: Solve for x
    x = 9,224.25/128.85
  6. Step 6: Final answer
    x = 71.59

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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.