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Finding the Fourth Proportional to 71.95, 107.90 and 20.58

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Solution

The fourth proportional to 71.95, 107.90 and 20.58 is: 30.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.95 : 107.90 = 20.58 : x
  2. Step 2: Convert to fraction form
    71.95/107.90 = 20.58/x
  3. Step 3: Cross multiply
    71.95x = 107.90 × 20.58
  4. Step 4: Simplify right side
    71.95x = 2,220.39
  5. Step 5: Solve for x
    x = 2,220.39/71.95
  6. Step 6: Final answer
    x = 30.86

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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.