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Finding the Fourth Proportional to 815.78, 1,223.57 and 238.65

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Solution

The fourth proportional to 815.78, 1,223.57 and 238.65 is: 357.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    815.78 : 1,223.57 = 238.65 : x
  2. Step 2: Convert to fraction form
    815.78/1,223.57 = 238.65/x
  3. Step 3: Cross multiply
    815.78x = 1,223.57 × 238.65
  4. Step 4: Simplify right side
    815.78x = 292,004.98
  5. Step 5: Solve for x
    x = 292,004.98/815.78
  6. Step 6: Final answer
    x = 357.95

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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.