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Finding the Fourth Proportional to 49.20, 67.86 and 30.78

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Solution

The fourth proportional to 49.20, 67.86 and 30.78 is: 42.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    49.20 : 67.86 = 30.78 : x
  2. Step 2: Convert to fraction form
    49.20/67.86 = 30.78/x
  3. Step 3: Cross multiply
    49.20x = 67.86 × 30.78
  4. Step 4: Simplify right side
    49.20x = 2,088.73
  5. Step 5: Solve for x
    x = 2,088.73/49.20
  6. Step 6: Final answer
    x = 42.45

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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.