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Finding the Fourth Proportional to 85.60, 128.47 and 82.61

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Solution

The fourth proportional to 85.60, 128.47 and 82.61 is: 123.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.60 : 128.47 = 82.61 : x
  2. Step 2: Convert to fraction form
    85.60/128.47 = 82.61/x
  3. Step 3: Cross multiply
    85.60x = 128.47 × 82.61
  4. Step 4: Simplify right side
    85.60x = 10,612.38
  5. Step 5: Solve for x
    x = 10,612.38/85.60
  6. Step 6: Final answer
    x = 123.98

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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.