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Finding the Fourth Proportional to 128.88, 192.80 and 108.64

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Solution

The fourth proportional to 128.88, 192.80 and 108.64 is: 162.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.88 : 192.80 = 108.64 : x
  2. Step 2: Convert to fraction form
    128.88/192.80 = 108.64/x
  3. Step 3: Cross multiply
    128.88x = 192.80 × 108.64
  4. Step 4: Simplify right side
    128.88x = 20,945.79
  5. Step 5: Solve for x
    x = 20,945.79/128.88
  6. Step 6: Final answer
    x = 162.52

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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.