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Finding the Fourth Proportional to 826.34, 1,238.36 and 642.90

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Solution

The fourth proportional to 826.34, 1,238.36 and 642.90 is: 963.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    826.34 : 1,238.36 = 642.90 : x
  2. Step 2: Convert to fraction form
    826.34/1,238.36 = 642.90/x
  3. Step 3: Cross multiply
    826.34x = 1,238.36 × 642.90
  4. Step 4: Simplify right side
    826.34x = 796,141.64
  5. Step 5: Solve for x
    x = 796,141.64/826.34
  6. Step 6: Final answer
    x = 963.46

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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.