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Finding the Fourth Proportional to 85.27, 128.11 and 80.67

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Solution

The fourth proportional to 85.27, 128.11 and 80.67 is: 121.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.27 : 128.11 = 80.67 : x
  2. Step 2: Convert to fraction form
    85.27/128.11 = 80.67/x
  3. Step 3: Cross multiply
    85.27x = 128.11 × 80.67
  4. Step 4: Simplify right side
    85.27x = 10,334.63
  5. Step 5: Solve for x
    x = 10,334.63/85.27
  6. Step 6: Final answer
    x = 121.20

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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.