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Finding the Fourth Proportional to 21.53, 32.31 and 20.43

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Solution

The fourth proportional to 21.53, 32.31 and 20.43 is: 30.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.53 : 32.31 = 20.43 : x
  2. Step 2: Convert to fraction form
    21.53/32.31 = 20.43/x
  3. Step 3: Cross multiply
    21.53x = 32.31 × 20.43
  4. Step 4: Simplify right side
    21.53x = 660.09
  5. Step 5: Solve for x
    x = 660.09/21.53
  6. Step 6: Final answer
    x = 30.66

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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.