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Finding the Fourth Proportional to 47.69, 71.56 and 20.65

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Solution

The fourth proportional to 47.69, 71.56 and 20.65 is: 30.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    47.69 : 71.56 = 20.65 : x
  2. Step 2: Convert to fraction form
    47.69/71.56 = 20.65/x
  3. Step 3: Cross multiply
    47.69x = 71.56 × 20.65
  4. Step 4: Simplify right side
    47.69x = 1,477.71
  5. Step 5: Solve for x
    x = 1,477.71/47.69
  6. Step 6: Final answer
    x = 30.99

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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.