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Finding the Fourth Proportional to 122.80, 183.80 and 76.40

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Solution

The fourth proportional to 122.80, 183.80 and 76.40 is: 114.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    122.80 : 183.80 = 76.40 : x
  2. Step 2: Convert to fraction form
    122.80/183.80 = 76.40/x
  3. Step 3: Cross multiply
    122.80x = 183.80 × 76.40
  4. Step 4: Simplify right side
    122.80x = 14,042.32
  5. Step 5: Solve for x
    x = 14,042.32/122.80
  6. Step 6: Final answer
    x = 114.35

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.