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Finding the Fourth Proportional to 71.88, 107.82 and 20.53

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Solution

The fourth proportional to 71.88, 107.82 and 20.53 is: 30.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.88 : 107.82 = 20.53 : x
  2. Step 2: Convert to fraction form
    71.88/107.82 = 20.53/x
  3. Step 3: Cross multiply
    71.88x = 107.82 × 20.53
  4. Step 4: Simplify right side
    71.88x = 2,213.68
  5. Step 5: Solve for x
    x = 2,213.68/71.88
  6. Step 6: Final answer
    x = 30.80

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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.