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Finding the Fourth Proportional to 21.55, 32.51 and 20.31

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Solution

The fourth proportional to 21.55, 32.51 and 20.31 is: 30.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.55 : 32.51 = 20.31 : x
  2. Step 2: Convert to fraction form
    21.55/32.51 = 20.31/x
  3. Step 3: Cross multiply
    21.55x = 32.51 × 20.31
  4. Step 4: Simplify right side
    21.55x = 660.12
  5. Step 5: Solve for x
    x = 660.12/21.55
  6. Step 6: Final answer
    x = 30.63

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.