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Finding the Fourth Proportional to 819.68, 1,132.12 and 644.80

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Solution

The fourth proportional to 819.68, 1,132.12 and 644.80 is: 890.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.68 : 1,132.12 = 644.80 : x
  2. Step 2: Convert to fraction form
    819.68/1,132.12 = 644.80/x
  3. Step 3: Cross multiply
    819.68x = 1,132.12 × 644.80
  4. Step 4: Simplify right side
    819.68x = 729,990.98
  5. Step 5: Solve for x
    x = 729,990.98/819.68
  6. Step 6: Final answer
    x = 890.58

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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.