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Finding the Fourth Proportional to 821.83, 1,235.31 and 515.65

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Solution

The fourth proportional to 821.83, 1,235.31 and 515.65 is: 775.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.83 : 1,235.31 = 515.65 : x
  2. Step 2: Convert to fraction form
    821.83/1,235.31 = 515.65/x
  3. Step 3: Cross multiply
    821.83x = 1,235.31 × 515.65
  4. Step 4: Simplify right side
    821.83x = 636,993.73
  5. Step 5: Solve for x
    x = 636,993.73/821.83
  6. Step 6: Final answer
    x = 775.09

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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.