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Finding the Fourth Proportional to 128.36, 190.81 and 127.64

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Solution

The fourth proportional to 128.36, 190.81 and 127.64 is: 189.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.36 : 190.81 = 127.64 : x
  2. Step 2: Convert to fraction form
    128.36/190.81 = 127.64/x
  3. Step 3: Cross multiply
    128.36x = 190.81 × 127.64
  4. Step 4: Simplify right side
    128.36x = 24,354.99
  5. Step 5: Solve for x
    x = 24,354.99/128.36
  6. Step 6: Final answer
    x = 189.74

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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.