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Finding the Fourth Proportional to 85.70, 129.04 and 75.68

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Solution

The fourth proportional to 85.70, 129.04 and 75.68 is: 113.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.70 : 129.04 = 75.68 : x
  2. Step 2: Convert to fraction form
    85.70/129.04 = 75.68/x
  3. Step 3: Cross multiply
    85.70x = 129.04 × 75.68
  4. Step 4: Simplify right side
    85.70x = 9,765.75
  5. Step 5: Solve for x
    x = 9,765.75/85.70
  6. Step 6: Final answer
    x = 113.95

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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.