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Finding the Fourth Proportional to 128.13, 191.91 and 100.64

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Solution

The fourth proportional to 128.13, 191.91 and 100.64 is: 150.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.13 : 191.91 = 100.64 : x
  2. Step 2: Convert to fraction form
    128.13/191.91 = 100.64/x
  3. Step 3: Cross multiply
    128.13x = 191.91 × 100.64
  4. Step 4: Simplify right side
    128.13x = 19,312.86
  5. Step 5: Solve for x
    x = 19,312.86/128.13
  6. Step 6: Final answer
    x = 150.73

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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.