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Finding the Fourth Proportional to 208.78, 311.42 and 191.08

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Solution

The fourth proportional to 208.78, 311.42 and 191.08 is: 285.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.78 : 311.42 = 191.08 : x
  2. Step 2: Convert to fraction form
    208.78/311.42 = 191.08/x
  3. Step 3: Cross multiply
    208.78x = 311.42 × 191.08
  4. Step 4: Simplify right side
    208.78x = 59,507.34
  5. Step 5: Solve for x
    x = 59,507.34/208.78
  6. Step 6: Final answer
    x = 285.03

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.