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Finding the Fourth Proportional to 31.81, 47.40 and 30.43

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Solution

The fourth proportional to 31.81, 47.40 and 30.43 is: 45.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.81 : 47.40 = 30.43 : x
  2. Step 2: Convert to fraction form
    31.81/47.40 = 30.43/x
  3. Step 3: Cross multiply
    31.81x = 47.40 × 30.43
  4. Step 4: Simplify right side
    31.81x = 1,442.38
  5. Step 5: Solve for x
    x = 1,442.38/31.81
  6. Step 6: Final answer
    x = 45.34

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.