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Finding the Fourth Proportional to 128.32, 191.14 and 121.48

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Solution

The fourth proportional to 128.32, 191.14 and 121.48 is: 180.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.32 : 191.14 = 121.48 : x
  2. Step 2: Convert to fraction form
    128.32/191.14 = 121.48/x
  3. Step 3: Cross multiply
    128.32x = 191.14 × 121.48
  4. Step 4: Simplify right side
    128.32x = 23,219.69
  5. Step 5: Solve for x
    x = 23,219.69/128.32
  6. Step 6: Final answer
    x = 180.95

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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.