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Finding the Fourth Proportional to 828, 1,239.12 and 780.66

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Solution

The fourth proportional to 828, 1,239.12 and 780.66 is: 1,168.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    828 : 1,239.12 = 780.66 : x
  2. Step 2: Convert to fraction form
    828/1,239.12 = 780.66/x
  3. Step 3: Cross multiply
    828x = 1,239.12 × 780.66
  4. Step 4: Simplify right side
    828x = 967,331.42
  5. Step 5: Solve for x
    x = 967,331.42/828
  6. Step 6: Final answer
    x = 1,168.27

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.