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Finding the Fourth Proportional to 121.80, 183.32 and 85.96

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Solution

The fourth proportional to 121.80, 183.32 and 85.96 is: 129.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.80 : 183.32 = 85.96 : x
  2. Step 2: Convert to fraction form
    121.80/183.32 = 85.96/x
  3. Step 3: Cross multiply
    121.80x = 183.32 × 85.96
  4. Step 4: Simplify right side
    121.80x = 15,758.19
  5. Step 5: Solve for x
    x = 15,758.19/121.80
  6. Step 6: Final answer
    x = 129.38

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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.