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Finding the Fourth Proportional to 31.43, 47.15 and 13.40

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Solution

The fourth proportional to 31.43, 47.15 and 13.40 is: 20.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.43 : 47.15 = 13.40 : x
  2. Step 2: Convert to fraction form
    31.43/47.15 = 13.40/x
  3. Step 3: Cross multiply
    31.43x = 47.15 × 13.40
  4. Step 4: Simplify right side
    31.43x = 631.81
  5. Step 5: Solve for x
    x = 631.81/31.43
  6. Step 6: Final answer
    x = 20.10

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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.