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Finding the Fourth Proportional to 815.45, 1,223.49 and 321.99

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Solution

The fourth proportional to 815.45, 1,223.49 and 321.99 is: 483.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.45 : 1,223.49 = 321.99 : x
  2. Step 2: Convert to fraction form
    815.45/1,223.49 = 321.99/x
  3. Step 3: Cross multiply
    815.45x = 1,223.49 × 321.99
  4. Step 4: Simplify right side
    815.45x = 393,951.55
  5. Step 5: Solve for x
    x = 393,951.55/815.45
  6. Step 6: Final answer
    x = 483.11

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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.