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Finding the Fourth Proportional to 826.40, 1,240.68 and 517.40

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Solution

The fourth proportional to 826.40, 1,240.68 and 517.40 is: 776.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.40 : 1,240.68 = 517.40 : x
  2. Step 2: Convert to fraction form
    826.40/1,240.68 = 517.40/x
  3. Step 3: Cross multiply
    826.40x = 1,240.68 × 517.40
  4. Step 4: Simplify right side
    826.40x = 641,927.83
  5. Step 5: Solve for x
    x = 641,927.83/826.40
  6. Step 6: Final answer
    x = 776.78

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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.