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Finding the Fourth Proportional to 311.10, 428.34 and 261.87

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Solution

The fourth proportional to 311.10, 428.34 and 261.87 is: 360.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.10 : 428.34 = 261.87 : x
  2. Step 2: Convert to fraction form
    311.10/428.34 = 261.87/x
  3. Step 3: Cross multiply
    311.10x = 428.34 × 261.87
  4. Step 4: Simplify right side
    311.10x = 112,169.40
  5. Step 5: Solve for x
    x = 112,169.40/311.10
  6. Step 6: Final answer
    x = 360.56

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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.