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Finding the Fourth Proportional to 826.78, 1,240.28 and 339.90

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Solution

The fourth proportional to 826.78, 1,240.28 and 339.90 is: 509.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.78 : 1,240.28 = 339.90 : x
  2. Step 2: Convert to fraction form
    826.78/1,240.28 = 339.90/x
  3. Step 3: Cross multiply
    826.78x = 1,240.28 × 339.90
  4. Step 4: Simplify right side
    826.78x = 421,571.17
  5. Step 5: Solve for x
    x = 421,571.17/826.78
  6. Step 6: Final answer
    x = 509.90

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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.