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Finding the Fourth Proportional to 128.65, 192.14 and 115.15

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Solution

The fourth proportional to 128.65, 192.14 and 115.15 is: 171.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.65 : 192.14 = 115.15 : x
  2. Step 2: Convert to fraction form
    128.65/192.14 = 115.15/x
  3. Step 3: Cross multiply
    128.65x = 192.14 × 115.15
  4. Step 4: Simplify right side
    128.65x = 22,124.92
  5. Step 5: Solve for x
    x = 22,124.92/128.65
  6. Step 6: Final answer
    x = 171.98

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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.