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Finding the Fourth Proportional to 85.89, 129.29 and 80.63

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Solution

The fourth proportional to 85.89, 129.29 and 80.63 is: 121.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.89 : 129.29 = 80.63 : x
  2. Step 2: Convert to fraction form
    85.89/129.29 = 80.63/x
  3. Step 3: Cross multiply
    85.89x = 129.29 × 80.63
  4. Step 4: Simplify right side
    85.89x = 10,424.21
  5. Step 5: Solve for x
    x = 10,424.21/85.89
  6. Step 6: Final answer
    x = 121.37

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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.