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Finding the Fourth Proportional to 19.71, 27.20 and 12.45

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Solution

The fourth proportional to 19.71, 27.20 and 12.45 is: 17.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.71 : 27.20 = 12.45 : x
  2. Step 2: Convert to fraction form
    19.71/27.20 = 12.45/x
  3. Step 3: Cross multiply
    19.71x = 27.20 × 12.45
  4. Step 4: Simplify right side
    19.71x = 338.77
  5. Step 5: Solve for x
    x = 338.77/19.71
  6. Step 6: Final answer
    x = 17.19

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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.