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Finding the Fourth Proportional to 19.79, 27.28 and 15.91

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Solution

The fourth proportional to 19.79, 27.28 and 15.91 is: 21.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.79 : 27.28 = 15.91 : x
  2. Step 2: Convert to fraction form
    19.79/27.28 = 15.91/x
  3. Step 3: Cross multiply
    19.79x = 27.28 × 15.91
  4. Step 4: Simplify right side
    19.79x = 433.98
  5. Step 5: Solve for x
    x = 433.98/19.79
  6. Step 6: Final answer
    x = 21.93

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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.