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Finding the Fourth Proportional to 31.80, 43.92 and 30

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Solution

The fourth proportional to 31.80, 43.92 and 30 is: 41.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.80 : 43.92 = 30 : x
  2. Step 2: Convert to fraction form
    31.80/43.92 = 30/x
  3. Step 3: Cross multiply
    31.80x = 43.92 × 30
  4. Step 4: Simplify right side
    31.80x = 1,317.60
  5. Step 5: Solve for x
    x = 1,317.60/31.80
  6. Step 6: Final answer
    x = 41.43

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.