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Finding the Fourth Proportional to 143.31, 215.04 and 85.56

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Solution

The fourth proportional to 143.31, 215.04 and 85.56 is: 128.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    143.31 : 215.04 = 85.56 : x
  2. Step 2: Convert to fraction form
    143.31/215.04 = 85.56/x
  3. Step 3: Cross multiply
    143.31x = 215.04 × 85.56
  4. Step 4: Simplify right side
    143.31x = 18,398.82
  5. Step 5: Solve for x
    x = 18,398.82/143.31
  6. Step 6: Final answer
    x = 128.38

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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.