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Finding the Fourth Proportional to 19.68, 27.18 and 15.40

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Solution

The fourth proportional to 19.68, 27.18 and 15.40 is: 21.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.68 : 27.18 = 15.40 : x
  2. Step 2: Convert to fraction form
    19.68/27.18 = 15.40/x
  3. Step 3: Cross multiply
    19.68x = 27.18 × 15.40
  4. Step 4: Simplify right side
    19.68x = 418.57
  5. Step 5: Solve for x
    x = 418.57/19.68
  6. Step 6: Final answer
    x = 21.27

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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.