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Finding the Fourth Proportional to 19.31, 28.78 and 18.91

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Solution

The fourth proportional to 19.31, 28.78 and 18.91 is: 28.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.31 : 28.78 = 18.91 : x
  2. Step 2: Convert to fraction form
    19.31/28.78 = 18.91/x
  3. Step 3: Cross multiply
    19.31x = 28.78 × 18.91
  4. Step 4: Simplify right side
    19.31x = 544.23
  5. Step 5: Solve for x
    x = 544.23/19.31
  6. Step 6: Final answer
    x = 28.18

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.