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Finding the Fourth Proportional to 31.39, 47.09 and 9.72

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Solution

The fourth proportional to 31.39, 47.09 and 9.72 is: 14.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.39 : 47.09 = 9.72 : x
  2. Step 2: Convert to fraction form
    31.39/47.09 = 9.72/x
  3. Step 3: Cross multiply
    31.39x = 47.09 × 9.72
  4. Step 4: Simplify right side
    31.39x = 457.72
  5. Step 5: Solve for x
    x = 457.72/31.39
  6. Step 6: Final answer
    x = 14.58

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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.