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Finding the Fourth Proportional to 819.78, 1,130.43 and 644.82

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Solution

The fourth proportional to 819.78, 1,130.43 and 644.82 is: 889.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.78 : 1,130.43 = 644.82 : x
  2. Step 2: Convert to fraction form
    819.78/1,130.43 = 644.82/x
  3. Step 3: Cross multiply
    819.78x = 1,130.43 × 644.82
  4. Step 4: Simplify right side
    819.78x = 728,923.87
  5. Step 5: Solve for x
    x = 728,923.87/819.78
  6. Step 6: Final answer
    x = 889.17

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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.