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Finding the Fourth Proportional to 128.60, 191.99 and 105.82

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Solution

The fourth proportional to 128.60, 191.99 and 105.82 is: 157.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.60 : 191.99 = 105.82 : x
  2. Step 2: Convert to fraction form
    128.60/191.99 = 105.82/x
  3. Step 3: Cross multiply
    128.60x = 191.99 × 105.82
  4. Step 4: Simplify right side
    128.60x = 20,316.17
  5. Step 5: Solve for x
    x = 20,316.17/128.60
  6. Step 6: Final answer
    x = 157.98

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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.