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Finding the Fourth Proportional to 38.86, 53.63 and 21.61

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Solution

The fourth proportional to 38.86, 53.63 and 21.61 is: 29.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.86 : 53.63 = 21.61 : x
  2. Step 2: Convert to fraction form
    38.86/53.63 = 21.61/x
  3. Step 3: Cross multiply
    38.86x = 53.63 × 21.61
  4. Step 4: Simplify right side
    38.86x = 1,158.90
  5. Step 5: Solve for x
    x = 1,158.90/38.86
  6. Step 6: Final answer
    x = 29.82

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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.