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Finding the Fourth Proportional to 815.78, 1,223.84 and 382.70

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Solution

The fourth proportional to 815.78, 1,223.84 and 382.70 is: 574.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.78 : 1,223.84 = 382.70 : x
  2. Step 2: Convert to fraction form
    815.78/1,223.84 = 382.70/x
  3. Step 3: Cross multiply
    815.78x = 1,223.84 × 382.70
  4. Step 4: Simplify right side
    815.78x = 468,355.54
  5. Step 5: Solve for x
    x = 468,355.54/815.78
  6. Step 6: Final answer
    x = 574.12

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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.