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Finding the Fourth Proportional to 122.79, 169.40 and 83.40

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Solution

The fourth proportional to 122.79, 169.40 and 83.40 is: 115.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.79 : 169.40 = 83.40 : x
  2. Step 2: Convert to fraction form
    122.79/169.40 = 83.40/x
  3. Step 3: Cross multiply
    122.79x = 169.40 × 83.40
  4. Step 4: Simplify right side
    122.79x = 14,127.54
  5. Step 5: Solve for x
    x = 14,127.54/122.79
  6. Step 6: Final answer
    x = 115.05

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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.