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Finding the Fourth Proportional to 23.15, 31.91 and 15.86

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Solution

The fourth proportional to 23.15, 31.91 and 15.86 is: 21.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    23.15 : 31.91 = 15.86 : x
  2. Step 2: Convert to fraction form
    23.15/31.91 = 15.86/x
  3. Step 3: Cross multiply
    23.15x = 31.91 × 15.86
  4. Step 4: Simplify right side
    23.15x = 506.09
  5. Step 5: Solve for x
    x = 506.09/23.15
  6. Step 6: Final answer
    x = 21.86

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.