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Finding the Fourth Proportional to 38.78, 58.20 and 18.50

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Solution

The fourth proportional to 38.78, 58.20 and 18.50 is: 27.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    38.78 : 58.20 = 18.50 : x
  2. Step 2: Convert to fraction form
    38.78/58.20 = 18.50/x
  3. Step 3: Cross multiply
    38.78x = 58.20 × 18.50
  4. Step 4: Simplify right side
    38.78x = 1,076.70
  5. Step 5: Solve for x
    x = 1,076.70/38.78
  6. Step 6: Final answer
    x = 27.76

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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.