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Finding the Fourth Proportional to 85.59, 128.39 and 55.22

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Solution

The fourth proportional to 85.59, 128.39 and 55.22 is: 82.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.59 : 128.39 = 55.22 : x
  2. Step 2: Convert to fraction form
    85.59/128.39 = 55.22/x
  3. Step 3: Cross multiply
    85.59x = 128.39 × 55.22
  4. Step 4: Simplify right side
    85.59x = 7,088.78
  5. Step 5: Solve for x
    x = 7,088.78/85.59
  6. Step 6: Final answer
    x = 82.82

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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.