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Finding the Fourth Proportional to 811.43, 1,119.81 and 636.47

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Solution

The fourth proportional to 811.43, 1,119.81 and 636.47 is: 878.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    811.43 : 1,119.81 = 636.47 : x
  2. Step 2: Convert to fraction form
    811.43/1,119.81 = 636.47/x
  3. Step 3: Cross multiply
    811.43x = 1,119.81 × 636.47
  4. Step 4: Simplify right side
    811.43x = 712,719.87
  5. Step 5: Solve for x
    x = 712,719.87/811.43
  6. Step 6: Final answer
    x = 878.36

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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.