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Finding the Fourth Proportional to 49.78, 74.68 and 20.50

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Solution

The fourth proportional to 49.78, 74.68 and 20.50 is: 30.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    49.78 : 74.68 = 20.50 : x
  2. Step 2: Convert to fraction form
    49.78/74.68 = 20.50/x
  3. Step 3: Cross multiply
    49.78x = 74.68 × 20.50
  4. Step 4: Simplify right side
    49.78x = 1,530.94
  5. Step 5: Solve for x
    x = 1,530.94/49.78
  6. Step 6: Final answer
    x = 30.75

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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.