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Finding the Fourth Proportional to 47.81, 71.72 and 20.77

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Solution

The fourth proportional to 47.81, 71.72 and 20.77 is: 31.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.81 : 71.72 = 20.77 : x
  2. Step 2: Convert to fraction form
    47.81/71.72 = 20.77/x
  3. Step 3: Cross multiply
    47.81x = 71.72 × 20.77
  4. Step 4: Simplify right side
    47.81x = 1,489.50
  5. Step 5: Solve for x
    x = 1,489.50/47.81
  6. Step 6: Final answer
    x = 31.15

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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.