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Finding the Fourth Proportional to 819.28, 1,129.74 and 644.32

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Solution

The fourth proportional to 819.28, 1,129.74 and 644.32 is: 888.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.28 : 1,129.74 = 644.32 : x
  2. Step 2: Convert to fraction form
    819.28/1,129.74 = 644.32/x
  3. Step 3: Cross multiply
    819.28x = 1,129.74 × 644.32
  4. Step 4: Simplify right side
    819.28x = 727,914.08
  5. Step 5: Solve for x
    x = 727,914.08/819.28
  6. Step 6: Final answer
    x = 888.48

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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.