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Finding the Fourth Proportional to 85.54, 128.25 and 72.70

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Solution

The fourth proportional to 85.54, 128.25 and 72.70 is: 109.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.54 : 128.25 = 72.70 : x
  2. Step 2: Convert to fraction form
    85.54/128.25 = 72.70/x
  3. Step 3: Cross multiply
    85.54x = 128.25 × 72.70
  4. Step 4: Simplify right side
    85.54x = 9,323.78
  5. Step 5: Solve for x
    x = 9,323.78/85.54
  6. Step 6: Final answer
    x = 109.01

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.