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Finding the Fourth Proportional to 21.07, 31.61 and 12.06

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Solution

The fourth proportional to 21.07, 31.61 and 12.06 is: 18.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    21.07 : 31.61 = 12.06 : x
  2. Step 2: Convert to fraction form
    21.07/31.61 = 12.06/x
  3. Step 3: Cross multiply
    21.07x = 31.61 × 12.06
  4. Step 4: Simplify right side
    21.07x = 381.22
  5. Step 5: Solve for x
    x = 381.22/21.07
  6. Step 6: Final answer
    x = 18.09

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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.