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Finding the Fourth Proportional to 820.26, 1,131.98 and 643.43

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Solution

The fourth proportional to 820.26, 1,131.98 and 643.43 is: 887.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    820.26 : 1,131.98 = 643.43 : x
  2. Step 2: Convert to fraction form
    820.26/1,131.98 = 643.43/x
  3. Step 3: Cross multiply
    820.26x = 1,131.98 × 643.43
  4. Step 4: Simplify right side
    820.26x = 728,349.50
  5. Step 5: Solve for x
    x = 728,349.50/820.26
  6. Step 6: Final answer
    x = 887.95

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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.