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Finding the Fourth Proportional to 128.25, 191.52 and 105.36

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Solution

The fourth proportional to 128.25, 191.52 and 105.36 is: 157.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.25 : 191.52 = 105.36 : x
  2. Step 2: Convert to fraction form
    128.25/191.52 = 105.36/x
  3. Step 3: Cross multiply
    128.25x = 191.52 × 105.36
  4. Step 4: Simplify right side
    128.25x = 20,178.55
  5. Step 5: Solve for x
    x = 20,178.55/128.25
  6. Step 6: Final answer
    x = 157.34

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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.