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Finding the Fourth Proportional to 128.79, 191.81 and 127.43

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Solution

The fourth proportional to 128.79, 191.81 and 127.43 is: 189.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.79 : 191.81 = 127.43 : x
  2. Step 2: Convert to fraction form
    128.79/191.81 = 127.43/x
  3. Step 3: Cross multiply
    128.79x = 191.81 × 127.43
  4. Step 4: Simplify right side
    128.79x = 24,440.75
  5. Step 5: Solve for x
    x = 24,440.75/128.79
  6. Step 6: Final answer
    x = 189.77

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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.