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Finding the Fourth Proportional to 89.31, 123.21 and 67.20

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Solution

The fourth proportional to 89.31, 123.21 and 67.20 is: 92.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.31 : 123.21 = 67.20 : x
  2. Step 2: Convert to fraction form
    89.31/123.21 = 67.20/x
  3. Step 3: Cross multiply
    89.31x = 123.21 × 67.20
  4. Step 4: Simplify right side
    89.31x = 8,279.71
  5. Step 5: Solve for x
    x = 8,279.71/89.31
  6. Step 6: Final answer
    x = 92.71

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.