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Finding the Fourth Proportional to 28.79, 43.20 and 19.78

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Solution

The fourth proportional to 28.79, 43.20 and 19.78 is: 29.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.79 : 43.20 = 19.78 : x
  2. Step 2: Convert to fraction form
    28.79/43.20 = 19.78/x
  3. Step 3: Cross multiply
    28.79x = 43.20 × 19.78
  4. Step 4: Simplify right side
    28.79x = 854.50
  5. Step 5: Solve for x
    x = 854.50/28.79
  6. Step 6: Final answer
    x = 29.68

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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.