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Finding the Fourth Proportional to 782.82, 1,079.01 and 642.69

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Solution

The fourth proportional to 782.82, 1,079.01 and 642.69 is: 885.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.82 : 1,079.01 = 642.69 : x
  2. Step 2: Convert to fraction form
    782.82/1,079.01 = 642.69/x
  3. Step 3: Cross multiply
    782.82x = 1,079.01 × 642.69
  4. Step 4: Simplify right side
    782.82x = 693,468.94
  5. Step 5: Solve for x
    x = 693,468.94/782.82
  6. Step 6: Final answer
    x = 885.86

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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.