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Finding the Fourth Proportional to 815.20, 1,220.69 and 540.43

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Solution

The fourth proportional to 815.20, 1,220.69 and 540.43 is: 809.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.20 : 1,220.69 = 540.43 : x
  2. Step 2: Convert to fraction form
    815.20/1,220.69 = 540.43/x
  3. Step 3: Cross multiply
    815.20x = 1,220.69 × 540.43
  4. Step 4: Simplify right side
    815.20x = 659,695.80
  5. Step 5: Solve for x
    x = 659,695.80/815.20
  6. Step 6: Final answer
    x = 809.25

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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.