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Finding the Fourth Proportional to 815.21, 1,222.92 and 259.73

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Solution

The fourth proportional to 815.21, 1,222.92 and 259.73 is: 389.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.21 : 1,222.92 = 259.73 : x
  2. Step 2: Convert to fraction form
    815.21/1,222.92 = 259.73/x
  3. Step 3: Cross multiply
    815.21x = 1,222.92 × 259.73
  4. Step 4: Simplify right side
    815.21x = 317,622.90
  5. Step 5: Solve for x
    x = 317,622.90/815.21
  6. Step 6: Final answer
    x = 389.62

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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.