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Finding the Fourth Proportional to 31.58, 47.25 and 20.87

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Solution

The fourth proportional to 31.58, 47.25 and 20.87 is: 31.22

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.58 : 47.25 = 20.87 : x
  2. Step 2: Convert to fraction form
    31.58/47.25 = 20.87/x
  3. Step 3: Cross multiply
    31.58x = 47.25 × 20.87
  4. Step 4: Simplify right side
    31.58x = 985.87
  5. Step 5: Solve for x
    x = 985.87/31.58
  6. Step 6: Final answer
    x = 31.22

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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.