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Finding the Fourth Proportional to 28.78, 43.20 and 19.64

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Solution

The fourth proportional to 28.78, 43.20 and 19.64 is: 29.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.78 : 43.20 = 19.64 : x
  2. Step 2: Convert to fraction form
    28.78/43.20 = 19.64/x
  3. Step 3: Cross multiply
    28.78x = 43.20 × 19.64
  4. Step 4: Simplify right side
    28.78x = 848.45
  5. Step 5: Solve for x
    x = 848.45/28.78
  6. Step 6: Final answer
    x = 29.48

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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.