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Finding the Fourth Proportional to 128.08, 191.87 and 99.17

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Solution

The fourth proportional to 128.08, 191.87 and 99.17 is: 148.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.08 : 191.87 = 99.17 : x
  2. Step 2: Convert to fraction form
    128.08/191.87 = 99.17/x
  3. Step 3: Cross multiply
    128.08x = 191.87 × 99.17
  4. Step 4: Simplify right side
    128.08x = 19,027.25
  5. Step 5: Solve for x
    x = 19,027.25/128.08
  6. Step 6: Final answer
    x = 148.56

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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.