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Finding the Fourth Proportional to 128.42, 191.92 and 104.40

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Solution

The fourth proportional to 128.42, 191.92 and 104.40 is: 156.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.42 : 191.92 = 104.40 : x
  2. Step 2: Convert to fraction form
    128.42/191.92 = 104.40/x
  3. Step 3: Cross multiply
    128.42x = 191.92 × 104.40
  4. Step 4: Simplify right side
    128.42x = 20,036.45
  5. Step 5: Solve for x
    x = 20,036.45/128.42
  6. Step 6: Final answer
    x = 156.02

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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.