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Finding the Fourth Proportional to 41.20, 56.80 and 39.40

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Solution

The fourth proportional to 41.20, 56.80 and 39.40 is: 54.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    41.20 : 56.80 = 39.40 : x
  2. Step 2: Convert to fraction form
    41.20/56.80 = 39.40/x
  3. Step 3: Cross multiply
    41.20x = 56.80 × 39.40
  4. Step 4: Simplify right side
    41.20x = 2,237.92
  5. Step 5: Solve for x
    x = 2,237.92/41.20
  6. Step 6: Final answer
    x = 54.32

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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.