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Finding the Fourth Proportional to 815.50, 1,220.41 and 768.12

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Solution

The fourth proportional to 815.50, 1,220.41 and 768.12 is: 1,149.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.50 : 1,220.41 = 768.12 : x
  2. Step 2: Convert to fraction form
    815.50/1,220.41 = 768.12/x
  3. Step 3: Cross multiply
    815.50x = 1,220.41 × 768.12
  4. Step 4: Simplify right side
    815.50x = 937,421.33
  5. Step 5: Solve for x
    x = 937,421.33/815.50
  6. Step 6: Final answer
    x = 1,149.51

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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.