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Finding the Fourth Proportional to 812.87, 1,219.50 and 319.31

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Solution

The fourth proportional to 812.87, 1,219.50 and 319.31 is: 479.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.87 : 1,219.50 = 319.31 : x
  2. Step 2: Convert to fraction form
    812.87/1,219.50 = 319.31/x
  3. Step 3: Cross multiply
    812.87x = 1,219.50 × 319.31
  4. Step 4: Simplify right side
    812.87x = 389,392.45
  5. Step 5: Solve for x
    x = 389,392.45/812.87
  6. Step 6: Final answer
    x = 479.04

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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.