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Finding the Fourth Proportional to 128.81, 192.22 and 115.16

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Solution

The fourth proportional to 128.81, 192.22 and 115.16 is: 171.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.81 : 192.22 = 115.16 : x
  2. Step 2: Convert to fraction form
    128.81/192.22 = 115.16/x
  3. Step 3: Cross multiply
    128.81x = 192.22 × 115.16
  4. Step 4: Simplify right side
    128.81x = 22,134.81
  5. Step 5: Solve for x
    x = 22,134.81/128.81
  6. Step 6: Final answer
    x = 171.84

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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.