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Finding the Fourth Proportional to 21.79, 30.13 and 16.40

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Solution

The fourth proportional to 21.79, 30.13 and 16.40 is: 22.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.79 : 30.13 = 16.40 : x
  2. Step 2: Convert to fraction form
    21.79/30.13 = 16.40/x
  3. Step 3: Cross multiply
    21.79x = 30.13 × 16.40
  4. Step 4: Simplify right side
    21.79x = 494.13
  5. Step 5: Solve for x
    x = 494.13/21.79
  6. Step 6: Final answer
    x = 22.68

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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.