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Finding the Fourth Proportional to 159.42, 238.78 and 128.67

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Solution

The fourth proportional to 159.42, 238.78 and 128.67 is: 192.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    159.42 : 238.78 = 128.67 : x
  2. Step 2: Convert to fraction form
    159.42/238.78 = 128.67/x
  3. Step 3: Cross multiply
    159.42x = 238.78 × 128.67
  4. Step 4: Simplify right side
    159.42x = 30,723.09
  5. Step 5: Solve for x
    x = 30,723.09/159.42
  6. Step 6: Final answer
    x = 192.71

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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.