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Finding the Fourth Proportional to 47.64, 71.47 and 20.57

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Solution

The fourth proportional to 47.64, 71.47 and 20.57 is: 30.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.64 : 71.47 = 20.57 : x
  2. Step 2: Convert to fraction form
    47.64/71.47 = 20.57/x
  3. Step 3: Cross multiply
    47.64x = 71.47 × 20.57
  4. Step 4: Simplify right side
    47.64x = 1,470.09
  5. Step 5: Solve for x
    x = 1,470.09/47.64
  6. Step 6: Final answer
    x = 30.86

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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.