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Finding the Fourth Proportional to 90.33, 136.31 and 87.31

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Solution

The fourth proportional to 90.33, 136.31 and 87.31 is: 131.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.33 : 136.31 = 87.31 : x
  2. Step 2: Convert to fraction form
    90.33/136.31 = 87.31/x
  3. Step 3: Cross multiply
    90.33x = 136.31 × 87.31
  4. Step 4: Simplify right side
    90.33x = 11,901.23
  5. Step 5: Solve for x
    x = 11,901.23/90.33
  6. Step 6: Final answer
    x = 131.75

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.