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Finding the Fourth Proportional to 85.60, 128.38 and 34.28

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Solution

The fourth proportional to 85.60, 128.38 and 34.28 is: 51.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.60 : 128.38 = 34.28 : x
  2. Step 2: Convert to fraction form
    85.60/128.38 = 34.28/x
  3. Step 3: Cross multiply
    85.60x = 128.38 × 34.28
  4. Step 4: Simplify right side
    85.60x = 4,400.87
  5. Step 5: Solve for x
    x = 4,400.87/85.60
  6. Step 6: Final answer
    x = 51.41

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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.