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Finding the Fourth Proportional to 85.60, 129.22 and 84.70

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Solution

The fourth proportional to 85.60, 129.22 and 84.70 is: 127.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.60 : 129.22 = 84.70 : x
  2. Step 2: Convert to fraction form
    85.60/129.22 = 84.70/x
  3. Step 3: Cross multiply
    85.60x = 129.22 × 84.70
  4. Step 4: Simplify right side
    85.60x = 10,944.93
  5. Step 5: Solve for x
    x = 10,944.93/85.60
  6. Step 6: Final answer
    x = 127.86

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.