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Finding the Fourth Proportional to 21.40, 32.09 and 8.56

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Solution

The fourth proportional to 21.40, 32.09 and 8.56 is: 12.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.40 : 32.09 = 8.56 : x
  2. Step 2: Convert to fraction form
    21.40/32.09 = 8.56/x
  3. Step 3: Cross multiply
    21.40x = 32.09 × 8.56
  4. Step 4: Simplify right side
    21.40x = 274.69
  5. Step 5: Solve for x
    x = 274.69/21.40
  6. Step 6: Final answer
    x = 12.84

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.