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Finding the Fourth Proportional to 812.61, 1,218.87 and 219.65

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Solution

The fourth proportional to 812.61, 1,218.87 and 219.65 is: 329.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.61 : 1,218.87 = 219.65 : x
  2. Step 2: Convert to fraction form
    812.61/1,218.87 = 219.65/x
  3. Step 3: Cross multiply
    812.61x = 1,218.87 × 219.65
  4. Step 4: Simplify right side
    812.61x = 267,724.46
  5. Step 5: Solve for x
    x = 267,724.46/812.61
  6. Step 6: Final answer
    x = 329.46

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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.