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Finding the Fourth Proportional to 85.92, 129.50 and 80.35

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Solution

The fourth proportional to 85.92, 129.50 and 80.35 is: 121.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.92 : 129.50 = 80.35 : x
  2. Step 2: Convert to fraction form
    85.92/129.50 = 80.35/x
  3. Step 3: Cross multiply
    85.92x = 129.50 × 80.35
  4. Step 4: Simplify right side
    85.92x = 10,405.33
  5. Step 5: Solve for x
    x = 10,405.33/85.92
  6. Step 6: Final answer
    x = 121.10

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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.