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Finding the Fourth Proportional to 809.85, 1,216.80 and 517.50

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Solution

The fourth proportional to 809.85, 1,216.80 and 517.50 is: 777.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.85 : 1,216.80 = 517.50 : x
  2. Step 2: Convert to fraction form
    809.85/1,216.80 = 517.50/x
  3. Step 3: Cross multiply
    809.85x = 1,216.80 × 517.50
  4. Step 4: Simplify right side
    809.85x = 629,694
  5. Step 5: Solve for x
    x = 629,694/809.85
  6. Step 6: Final answer
    x = 777.54

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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.