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Finding the Fourth Proportional to 50.78, 70.10 and 39.85

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Solution

The fourth proportional to 50.78, 70.10 and 39.85 is: 55.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    50.78 : 70.10 = 39.85 : x
  2. Step 2: Convert to fraction form
    50.78/70.10 = 39.85/x
  3. Step 3: Cross multiply
    50.78x = 70.10 × 39.85
  4. Step 4: Simplify right side
    50.78x = 2,793.49
  5. Step 5: Solve for x
    x = 2,793.49/50.78
  6. Step 6: Final answer
    x = 55.01

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.