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Finding the Fourth Proportional to 112.31, 168.09 and 90.71

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Solution

The fourth proportional to 112.31, 168.09 and 90.71 is: 135.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    112.31 : 168.09 = 90.71 : x
  2. Step 2: Convert to fraction form
    112.31/168.09 = 90.71/x
  3. Step 3: Cross multiply
    112.31x = 168.09 × 90.71
  4. Step 4: Simplify right side
    112.31x = 15,247.44
  5. Step 5: Solve for x
    x = 15,247.44/112.31
  6. Step 6: Final answer
    x = 135.76

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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.