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Finding the Third Proportional to 311.50 and 378.50

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Solution

The third proportional to 311.50 and 378.50 is: 459.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    311.50 : 378.50 = 378.50 : x
  2. Step 2: Convert to fraction form
    311.50/378.50 = 378.50/x
  3. Step 3: Cross multiply
    311.50x = 378.50 × 378.50
  4. Step 4: Simplify right side
    311.50x = 143,262.25
  5. Step 5: Solve for x
    x = 143,262.25/311.50
  6. Step 6: Final answer
    x = 459.91

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Why These Related Problems?

These problems maintain the same ratio (1.22) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.