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Finding the Fourth Proportional to 38.25, 52.79 and 21

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Solution

The fourth proportional to 38.25, 52.79 and 21 is: 28.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.25 : 52.79 = 21 : x
  2. Step 2: Convert to fraction form
    38.25/52.79 = 21/x
  3. Step 3: Cross multiply
    38.25x = 52.79 × 21
  4. Step 4: Simplify right side
    38.25x = 1,108.49
  5. Step 5: Solve for x
    x = 1,108.49/38.25
  6. Step 6: Final answer
    x = 28.98

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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.