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Finding the Fourth Proportional to 815.28, 1,217.96 and 520.43

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Solution

The fourth proportional to 815.28, 1,217.96 and 520.43 is: 777.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.28 : 1,217.96 = 520.43 : x
  2. Step 2: Convert to fraction form
    815.28/1,217.96 = 520.43/x
  3. Step 3: Cross multiply
    815.28x = 1,217.96 × 520.43
  4. Step 4: Simplify right side
    815.28x = 633,862.92
  5. Step 5: Solve for x
    x = 633,862.92/815.28
  6. Step 6: Final answer
    x = 777.48

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.