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Finding the Fourth Proportional to 40.80, 61.20 and 28.74

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Solution

The fourth proportional to 40.80, 61.20 and 28.74 is: 43.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    40.80 : 61.20 = 28.74 : x
  2. Step 2: Convert to fraction form
    40.80/61.20 = 28.74/x
  3. Step 3: Cross multiply
    40.80x = 61.20 × 28.74
  4. Step 4: Simplify right side
    40.80x = 1,758.89
  5. Step 5: Solve for x
    x = 1,758.89/40.80
  6. Step 6: Final answer
    x = 43.11

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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.