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Finding the Fourth Proportional to 128.12, 192.21 and 41.47

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Solution

The fourth proportional to 128.12, 192.21 and 41.47 is: 62.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.12 : 192.21 = 41.47 : x
  2. Step 2: Convert to fraction form
    128.12/192.21 = 41.47/x
  3. Step 3: Cross multiply
    128.12x = 192.21 × 41.47
  4. Step 4: Simplify right side
    128.12x = 7,970.95
  5. Step 5: Solve for x
    x = 7,970.95/128.12
  6. Step 6: Final answer
    x = 62.21

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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.