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Finding the Fourth Proportional to 85.92, 128.24 and 73.72

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Solution

The fourth proportional to 85.92, 128.24 and 73.72 is: 110.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.92 : 128.24 = 73.72 : x
  2. Step 2: Convert to fraction form
    85.92/128.24 = 73.72/x
  3. Step 3: Cross multiply
    85.92x = 128.24 × 73.72
  4. Step 4: Simplify right side
    85.92x = 9,453.85
  5. Step 5: Solve for x
    x = 9,453.85/85.92
  6. Step 6: Final answer
    x = 110.03

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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.