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Finding the Fourth Proportional to 154.22, 231.42 and 85.70

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Solution

The fourth proportional to 154.22, 231.42 and 85.70 is: 128.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    154.22 : 231.42 = 85.70 : x
  2. Step 2: Convert to fraction form
    154.22/231.42 = 85.70/x
  3. Step 3: Cross multiply
    154.22x = 231.42 × 85.70
  4. Step 4: Simplify right side
    154.22x = 19,832.69
  5. Step 5: Solve for x
    x = 19,832.69/154.22
  6. Step 6: Final answer
    x = 128.60

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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.