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Finding the Fourth Proportional to 128.61, 192.91 and 43.17

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Solution

The fourth proportional to 128.61, 192.91 and 43.17 is: 64.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.61 : 192.91 = 43.17 : x
  2. Step 2: Convert to fraction form
    128.61/192.91 = 43.17/x
  3. Step 3: Cross multiply
    128.61x = 192.91 × 43.17
  4. Step 4: Simplify right side
    128.61x = 8,326.85
  5. Step 5: Solve for x
    x = 8,326.85/128.61
  6. Step 6: Final answer
    x = 64.75

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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.