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Finding the Fourth Proportional to 71.81, 107.68 and 66.20

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Solution

The fourth proportional to 71.81, 107.68 and 66.20 is: 99.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.81 : 107.68 = 66.20 : x
  2. Step 2: Convert to fraction form
    71.81/107.68 = 66.20/x
  3. Step 3: Cross multiply
    71.81x = 107.68 × 66.20
  4. Step 4: Simplify right side
    71.81x = 7,128.12
  5. Step 5: Solve for x
    x = 7,128.12/71.81
  6. Step 6: Final answer
    x = 99.26

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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.