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Finding the Fourth Proportional to 85.96, 128.79 and 51.62

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Solution

The fourth proportional to 85.96, 128.79 and 51.62 is: 77.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.96 : 128.79 = 51.62 : x
  2. Step 2: Convert to fraction form
    85.96/128.79 = 51.62/x
  3. Step 3: Cross multiply
    85.96x = 128.79 × 51.62
  4. Step 4: Simplify right side
    85.96x = 6,648.14
  5. Step 5: Solve for x
    x = 6,648.14/85.96
  6. Step 6: Final answer
    x = 77.34

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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.