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Finding the Fourth Proportional to 782.78, 1,079.12 and 561.66

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Solution

The fourth proportional to 782.78, 1,079.12 and 561.66 is: 774.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    782.78 : 1,079.12 = 561.66 : x
  2. Step 2: Convert to fraction form
    782.78/1,079.12 = 561.66/x
  3. Step 3: Cross multiply
    782.78x = 1,079.12 × 561.66
  4. Step 4: Simplify right side
    782.78x = 606,098.54
  5. Step 5: Solve for x
    x = 606,098.54/782.78
  6. Step 6: Final answer
    x = 774.29

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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.