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Finding the Fourth Proportional to 85, 126.79 and 72.22

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Solution

The fourth proportional to 85, 126.79 and 72.22 is: 107.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    85 : 126.79 = 72.22 : x
  2. Step 2: Convert to fraction form
    85/126.79 = 72.22/x
  3. Step 3: Cross multiply
    85x = 126.79 × 72.22
  4. Step 4: Simplify right side
    85x = 9,156.77
  5. Step 5: Solve for x
    x = 9,156.77/85
  6. Step 6: Final answer
    x = 107.73

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.