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Finding the Fourth Proportional to 128.22, 191.54 and 108.87

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Solution

The fourth proportional to 128.22, 191.54 and 108.87 is: 162.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.22 : 191.54 = 108.87 : x
  2. Step 2: Convert to fraction form
    128.22/191.54 = 108.87/x
  3. Step 3: Cross multiply
    128.22x = 191.54 × 108.87
  4. Step 4: Simplify right side
    128.22x = 20,852.42
  5. Step 5: Solve for x
    x = 20,852.42/128.22
  6. Step 6: Final answer
    x = 162.63

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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.