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Finding the Fourth Proportional to 85.74, 128.52 and 55.26

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Solution

The fourth proportional to 85.74, 128.52 and 55.26 is: 82.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.74 : 128.52 = 55.26 : x
  2. Step 2: Convert to fraction form
    85.74/128.52 = 55.26/x
  3. Step 3: Cross multiply
    85.74x = 128.52 × 55.26
  4. Step 4: Simplify right side
    85.74x = 7,102.02
  5. Step 5: Solve for x
    x = 7,102.02/85.74
  6. Step 6: Final answer
    x = 82.83

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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.