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Finding the Fourth Proportional to 21.81, 30.10 and 12.60

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Solution

The fourth proportional to 21.81, 30.10 and 12.60 is: 17.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.81 : 30.10 = 12.60 : x
  2. Step 2: Convert to fraction form
    21.81/30.10 = 12.60/x
  3. Step 3: Cross multiply
    21.81x = 30.10 × 12.60
  4. Step 4: Simplify right side
    21.81x = 379.23
  5. Step 5: Solve for x
    x = 379.23/21.81
  6. Step 6: Final answer
    x = 17.39

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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.