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Finding the Fourth Proportional to 825.10, 1,139.80 and 721.82

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Solution

The fourth proportional to 825.10, 1,139.80 and 721.82 is: 997.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    825.10 : 1,139.80 = 721.82 : x
  2. Step 2: Convert to fraction form
    825.10/1,139.80 = 721.82/x
  3. Step 3: Cross multiply
    825.10x = 1,139.80 × 721.82
  4. Step 4: Simplify right side
    825.10x = 822,730.44
  5. Step 5: Solve for x
    x = 822,730.44/825.10
  6. Step 6: Final answer
    x = 997.13

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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.