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Finding the Fourth Proportional to 85.96, 129.20 and 74.60

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Solution

The fourth proportional to 85.96, 129.20 and 74.60 is: 112.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.96 : 129.20 = 74.60 : x
  2. Step 2: Convert to fraction form
    85.96/129.20 = 74.60/x
  3. Step 3: Cross multiply
    85.96x = 129.20 × 74.60
  4. Step 4: Simplify right side
    85.96x = 9,638.32
  5. Step 5: Solve for x
    x = 9,638.32/85.96
  6. Step 6: Final answer
    x = 112.13

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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.