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Finding the Fourth Proportional to 128.87, 192.16 and 127.28

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Solution

The fourth proportional to 128.87, 192.16 and 127.28 is: 189.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.87 : 192.16 = 127.28 : x
  2. Step 2: Convert to fraction form
    128.87/192.16 = 127.28/x
  3. Step 3: Cross multiply
    128.87x = 192.16 × 127.28
  4. Step 4: Simplify right side
    128.87x = 24,458.58
  5. Step 5: Solve for x
    x = 24,458.58/128.87
  6. Step 6: Final answer
    x = 189.79

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.