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Finding the Fourth Proportional to 142.31, 212.54 and 121.81

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Solution

The fourth proportional to 142.31, 212.54 and 121.81 is: 181.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    142.31 : 212.54 = 121.81 : x
  2. Step 2: Convert to fraction form
    142.31/212.54 = 121.81/x
  3. Step 3: Cross multiply
    142.31x = 212.54 × 121.81
  4. Step 4: Simplify right side
    142.31x = 25,889.80
  5. Step 5: Solve for x
    x = 25,889.80/142.31
  6. Step 6: Final answer
    x = 181.93

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.