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Finding the Fourth Proportional to 31.40, 47.15 and 18.57

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Solution

The fourth proportional to 31.40, 47.15 and 18.57 is: 27.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.40 : 47.15 = 18.57 : x
  2. Step 2: Convert to fraction form
    31.40/47.15 = 18.57/x
  3. Step 3: Cross multiply
    31.40x = 47.15 × 18.57
  4. Step 4: Simplify right side
    31.40x = 875.38
  5. Step 5: Solve for x
    x = 875.38/31.40
  6. Step 6: Final answer
    x = 27.88

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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.