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Finding the Fourth Proportional to 819.76, 1,131.29 and 642.93

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Solution

The fourth proportional to 819.76, 1,131.29 and 642.93 is: 887.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    819.76 : 1,131.29 = 642.93 : x
  2. Step 2: Convert to fraction form
    819.76/1,131.29 = 642.93/x
  3. Step 3: Cross multiply
    819.76x = 1,131.29 × 642.93
  4. Step 4: Simplify right side
    819.76x = 727,340.28
  5. Step 5: Solve for x
    x = 727,340.28/819.76
  6. Step 6: Final answer
    x = 887.26

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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.