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Finding the Third Proportional to 280.85 and 421.87

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Solution

The third proportional to 280.85 and 421.87 is: 633.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.85 : 421.87 = 421.87 : x
  2. Step 2: Convert to fraction form
    280.85/421.87 = 421.87/x
  3. Step 3: Cross multiply
    280.85x = 421.87 × 421.87
  4. Step 4: Simplify right side
    280.85x = 177,972.95
  5. Step 5: Solve for x
    x = 177,972.95/280.85
  6. Step 6: Final answer
    x = 633.69

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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.