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Finding the Fourth Proportional to 85.96, 128.62 and 55.11

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Solution

The fourth proportional to 85.96, 128.62 and 55.11 is: 82.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.96 : 128.62 = 55.11 : x
  2. Step 2: Convert to fraction form
    85.96/128.62 = 55.11/x
  3. Step 3: Cross multiply
    85.96x = 128.62 × 55.11
  4. Step 4: Simplify right side
    85.96x = 7,088.80
  5. Step 5: Solve for x
    x = 7,088.80/85.96
  6. Step 6: Final answer
    x = 82.47

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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.