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Finding the Fourth Proportional to 828.72, 1,240.20 and 766.80

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Solution

The fourth proportional to 828.72, 1,240.20 and 766.80 is: 1,147.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    828.72 : 1,240.20 = 766.80 : x
  2. Step 2: Convert to fraction form
    828.72/1,240.20 = 766.80/x
  3. Step 3: Cross multiply
    828.72x = 1,240.20 × 766.80
  4. Step 4: Simplify right side
    828.72x = 950,985.36
  5. Step 5: Solve for x
    x = 950,985.36/828.72
  6. Step 6: Final answer
    x = 1,147.54

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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.