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Finding the Fourth Proportional to 121.56, 182.38 and 85

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Solution

The fourth proportional to 121.56, 182.38 and 85 is: 127.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.56 : 182.38 = 85 : x
  2. Step 2: Convert to fraction form
    121.56/182.38 = 85/x
  3. Step 3: Cross multiply
    121.56x = 182.38 × 85
  4. Step 4: Simplify right side
    121.56x = 15,502.09
  5. Step 5: Solve for x
    x = 15,502.09/121.56
  6. Step 6: Final answer
    x = 127.52

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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.