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Finding the Fourth Proportional to 72.26, 108.38 and 20.91

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Solution

The fourth proportional to 72.26, 108.38 and 20.91 is: 31.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    72.26 : 108.38 = 20.91 : x
  2. Step 2: Convert to fraction form
    72.26/108.38 = 20.91/x
  3. Step 3: Cross multiply
    72.26x = 108.38 × 20.91
  4. Step 4: Simplify right side
    72.26x = 2,266.23
  5. Step 5: Solve for x
    x = 2,266.23/72.26
  6. Step 6: Final answer
    x = 31.36

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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.