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Finding the Fourth Proportional to 122.72, 169.28 and 89.90

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Solution

The fourth proportional to 122.72, 169.28 and 89.90 is: 124.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.72 : 169.28 = 89.90 : x
  2. Step 2: Convert to fraction form
    122.72/169.28 = 89.90/x
  3. Step 3: Cross multiply
    122.72x = 169.28 × 89.90
  4. Step 4: Simplify right side
    122.72x = 15,218.27
  5. Step 5: Solve for x
    x = 15,218.27/122.72
  6. Step 6: Final answer
    x = 124.01

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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.