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Finding the Fourth Proportional to 85.82, 128.50 and 69.50

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Solution

The fourth proportional to 85.82, 128.50 and 69.50 is: 104.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.82 : 128.50 = 69.50 : x
  2. Step 2: Convert to fraction form
    85.82/128.50 = 69.50/x
  3. Step 3: Cross multiply
    85.82x = 128.50 × 69.50
  4. Step 4: Simplify right side
    85.82x = 8,930.75
  5. Step 5: Solve for x
    x = 8,930.75/85.82
  6. Step 6: Final answer
    x = 104.06

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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.