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Finding the Fourth Proportional to 21.69, 32.31 and 21.18

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Solution

The fourth proportional to 21.69, 32.31 and 21.18 is: 31.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.69 : 32.31 = 21.18 : x
  2. Step 2: Convert to fraction form
    21.69/32.31 = 21.18/x
  3. Step 3: Cross multiply
    21.69x = 32.31 × 21.18
  4. Step 4: Simplify right side
    21.69x = 684.33
  5. Step 5: Solve for x
    x = 684.33/21.69
  6. Step 6: Final answer
    x = 31.55

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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.