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Finding the Fourth Proportional to 31.40, 47.12 and 12.15

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Solution

The fourth proportional to 31.40, 47.12 and 12.15 is: 18.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.40 : 47.12 = 12.15 : x
  2. Step 2: Convert to fraction form
    31.40/47.12 = 12.15/x
  3. Step 3: Cross multiply
    31.40x = 47.12 × 12.15
  4. Step 4: Simplify right side
    31.40x = 572.50
  5. Step 5: Solve for x
    x = 572.50/31.40
  6. Step 6: Final answer
    x = 18.23

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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.