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Finding the Fourth Proportional to 85.76, 128.60 and 27.96

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Solution

The fourth proportional to 85.76, 128.60 and 27.96 is: 41.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.76 : 128.60 = 27.96 : x
  2. Step 2: Convert to fraction form
    85.76/128.60 = 27.96/x
  3. Step 3: Cross multiply
    85.76x = 128.60 × 27.96
  4. Step 4: Simplify right side
    85.76x = 3,596.02
  5. Step 5: Solve for x
    x = 3,596.02/85.76
  6. Step 6: Final answer
    x = 41.93

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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.