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Finding the Fourth Proportional to 826.25, 1,139.20 and 639.95

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Solution

The fourth proportional to 826.25, 1,139.20 and 639.95 is: 882.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.25 : 1,139.20 = 639.95 : x
  2. Step 2: Convert to fraction form
    826.25/1,139.20 = 639.95/x
  3. Step 3: Cross multiply
    826.25x = 1,139.20 × 639.95
  4. Step 4: Simplify right side
    826.25x = 729,023.74
  5. Step 5: Solve for x
    x = 729,023.74/826.25
  6. Step 6: Final answer
    x = 882.33

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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.