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Finding the Fourth Proportional to 36.90, 55.31 and 20.79

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Solution

The fourth proportional to 36.90, 55.31 and 20.79 is: 31.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    36.90 : 55.31 = 20.79 : x
  2. Step 2: Convert to fraction form
    36.90/55.31 = 20.79/x
  3. Step 3: Cross multiply
    36.90x = 55.31 × 20.79
  4. Step 4: Simplify right side
    36.90x = 1,149.79
  5. Step 5: Solve for x
    x = 1,149.79/36.90
  6. Step 6: Final answer
    x = 31.16

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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.