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Finding the Fourth Proportional to 128.32, 192.47 and 120.80

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Solution

The fourth proportional to 128.32, 192.47 and 120.80 is: 181.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.32 : 192.47 = 120.80 : x
  2. Step 2: Convert to fraction form
    128.32/192.47 = 120.80/x
  3. Step 3: Cross multiply
    128.32x = 192.47 × 120.80
  4. Step 4: Simplify right side
    128.32x = 23,250.38
  5. Step 5: Solve for x
    x = 23,250.38/128.32
  6. Step 6: Final answer
    x = 181.19

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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.