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Finding the Fourth Proportional to 85.28, 128.16 and 69.44

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Solution

The fourth proportional to 85.28, 128.16 and 69.44 is: 104.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.28 : 128.16 = 69.44 : x
  2. Step 2: Convert to fraction form
    85.28/128.16 = 69.44/x
  3. Step 3: Cross multiply
    85.28x = 128.16 × 69.44
  4. Step 4: Simplify right side
    85.28x = 8,899.43
  5. Step 5: Solve for x
    x = 8,899.43/85.28
  6. Step 6: Final answer
    x = 104.36

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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.