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Finding the Fourth Proportional to 311.50, 429.77 and 187.20

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Solution

The fourth proportional to 311.50, 429.77 and 187.20 is: 258.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.50 : 429.77 = 187.20 : x
  2. Step 2: Convert to fraction form
    311.50/429.77 = 187.20/x
  3. Step 3: Cross multiply
    311.50x = 429.77 × 187.20
  4. Step 4: Simplify right side
    311.50x = 80,452.94
  5. Step 5: Solve for x
    x = 80,452.94/311.50
  6. Step 6: Final answer
    x = 258.28

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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.