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Finding the Fourth Proportional to 31.31, 43.21 and 21.62

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Solution

The fourth proportional to 31.31, 43.21 and 21.62 is: 29.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    31.31 : 43.21 = 21.62 : x
  2. Step 2: Convert to fraction form
    31.31/43.21 = 21.62/x
  3. Step 3: Cross multiply
    31.31x = 43.21 × 21.62
  4. Step 4: Simplify right side
    31.31x = 934.20
  5. Step 5: Solve for x
    x = 934.20/31.31
  6. Step 6: Final answer
    x = 29.84

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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.