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Finding the Fourth Proportional to 21.43, 31.99 and 19.38

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Solution

The fourth proportional to 21.43, 31.99 and 19.38 is: 28.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.43 : 31.99 = 19.38 : x
  2. Step 2: Convert to fraction form
    21.43/31.99 = 19.38/x
  3. Step 3: Cross multiply
    21.43x = 31.99 × 19.38
  4. Step 4: Simplify right side
    21.43x = 619.97
  5. Step 5: Solve for x
    x = 619.97/21.43
  6. Step 6: Final answer
    x = 28.93

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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.