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Finding the Fourth Proportional to 157.31, 217.09 and 91.87

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Solution

The fourth proportional to 157.31, 217.09 and 91.87 is: 126.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    157.31 : 217.09 = 91.87 : x
  2. Step 2: Convert to fraction form
    157.31/217.09 = 91.87/x
  3. Step 3: Cross multiply
    157.31x = 217.09 × 91.87
  4. Step 4: Simplify right side
    157.31x = 19,944.44
  5. Step 5: Solve for x
    x = 19,944.44/157.31
  6. Step 6: Final answer
    x = 126.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.