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Finding the Fourth Proportional to 128.39, 192.69 and 84.93

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Solution

The fourth proportional to 128.39, 192.69 and 84.93 is: 127.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.39 : 192.69 = 84.93 : x
  2. Step 2: Convert to fraction form
    128.39/192.69 = 84.93/x
  3. Step 3: Cross multiply
    128.39x = 192.69 × 84.93
  4. Step 4: Simplify right side
    128.39x = 16,365.16
  5. Step 5: Solve for x
    x = 16,365.16/128.39
  6. Step 6: Final answer
    x = 127.47

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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.