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Finding the Fourth Proportional to 21.72, 32.42 and 20.13

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Solution

The fourth proportional to 21.72, 32.42 and 20.13 is: 30.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.72 : 32.42 = 20.13 : x
  2. Step 2: Convert to fraction form
    21.72/32.42 = 20.13/x
  3. Step 3: Cross multiply
    21.72x = 32.42 × 20.13
  4. Step 4: Simplify right side
    21.72x = 652.65
  5. Step 5: Solve for x
    x = 652.65/21.72
  6. Step 6: Final answer
    x = 30.05

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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.