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Finding the Fourth Proportional to 47.20, 70.81 and 20.13

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Solution

The fourth proportional to 47.20, 70.81 and 20.13 is: 30.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.20 : 70.81 = 20.13 : x
  2. Step 2: Convert to fraction form
    47.20/70.81 = 20.13/x
  3. Step 3: Cross multiply
    47.20x = 70.81 × 20.13
  4. Step 4: Simplify right side
    47.20x = 1,425.41
  5. Step 5: Solve for x
    x = 1,425.41/47.20
  6. Step 6: Final answer
    x = 30.20

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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.