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Finding the Fourth Proportional to 21.92, 29.88 and 21.78

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Solution

The fourth proportional to 21.92, 29.88 and 21.78 is: 29.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.92 : 29.88 = 21.78 : x
  2. Step 2: Convert to fraction form
    21.92/29.88 = 21.78/x
  3. Step 3: Cross multiply
    21.92x = 29.88 × 21.78
  4. Step 4: Simplify right side
    21.92x = 650.79
  5. Step 5: Solve for x
    x = 650.79/21.92
  6. Step 6: Final answer
    x = 29.70

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Why These Related Problems?

These problems maintain the same ratio (1.36) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.