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Finding the Fourth Proportional to 38.92, 53.71 and 21.43

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Solution

The fourth proportional to 38.92, 53.71 and 21.43 is: 29.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.92 : 53.71 = 21.43 : x
  2. Step 2: Convert to fraction form
    38.92/53.71 = 21.43/x
  3. Step 3: Cross multiply
    38.92x = 53.71 × 21.43
  4. Step 4: Simplify right side
    38.92x = 1,151.16
  5. Step 5: Solve for x
    x = 1,151.16/38.92
  6. Step 6: Final answer
    x = 29.58

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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.