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Finding the Fourth Proportional to 31.85, 47.42 and 30.36

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Solution

The fourth proportional to 31.85, 47.42 and 30.36 is: 45.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.85 : 47.42 = 30.36 : x
  2. Step 2: Convert to fraction form
    31.85/47.42 = 30.36/x
  3. Step 3: Cross multiply
    31.85x = 47.42 × 30.36
  4. Step 4: Simplify right side
    31.85x = 1,439.67
  5. Step 5: Solve for x
    x = 1,439.67/31.85
  6. Step 6: Final answer
    x = 45.20

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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.