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Finding the Fourth Proportional to 828.10, 1,239.42 and 691.42

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Solution

The fourth proportional to 828.10, 1,239.42 and 691.42 is: 1,034.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.10 : 1,239.42 = 691.42 : x
  2. Step 2: Convert to fraction form
    828.10/1,239.42 = 691.42/x
  3. Step 3: Cross multiply
    828.10x = 1,239.42 × 691.42
  4. Step 4: Simplify right side
    828.10x = 856,959.78
  5. Step 5: Solve for x
    x = 856,959.78/828.10
  6. Step 6: Final answer
    x = 1,034.85

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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.