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Finding the Fourth Proportional to 122.80, 169.56 and 86

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Solution

The fourth proportional to 122.80, 169.56 and 86 is: 118.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.80 : 169.56 = 86 : x
  2. Step 2: Convert to fraction form
    122.80/169.56 = 86/x
  3. Step 3: Cross multiply
    122.80x = 169.56 × 86
  4. Step 4: Simplify right side
    122.80x = 14,582.16
  5. Step 5: Solve for x
    x = 14,582.16/122.80
  6. Step 6: Final answer
    x = 118.75

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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.