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Finding the Fourth Proportional to 71.47, 107.21 and 66.91

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Solution

The fourth proportional to 71.47, 107.21 and 66.91 is: 100.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.47 : 107.21 = 66.91 : x
  2. Step 2: Convert to fraction form
    71.47/107.21 = 66.91/x
  3. Step 3: Cross multiply
    71.47x = 107.21 × 66.91
  4. Step 4: Simplify right side
    71.47x = 7,173.42
  5. Step 5: Solve for x
    x = 7,173.42/71.47
  6. Step 6: Final answer
    x = 100.37

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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.