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Finding the Fourth Proportional to 208.72, 312.60 and 190.90

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Solution

The fourth proportional to 208.72, 312.60 and 190.90 is: 285.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.72 : 312.60 = 190.90 : x
  2. Step 2: Convert to fraction form
    208.72/312.60 = 190.90/x
  3. Step 3: Cross multiply
    208.72x = 312.60 × 190.90
  4. Step 4: Simplify right side
    208.72x = 59,675.34
  5. Step 5: Solve for x
    x = 59,675.34/208.72
  6. Step 6: Final answer
    x = 285.91

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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.