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Finding the Fourth Proportional to 812.10, 1,219.29 and 447.15

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Solution

The fourth proportional to 812.10, 1,219.29 and 447.15 is: 671.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.10 : 1,219.29 = 447.15 : x
  2. Step 2: Convert to fraction form
    812.10/1,219.29 = 447.15/x
  3. Step 3: Cross multiply
    812.10x = 1,219.29 × 447.15
  4. Step 4: Simplify right side
    812.10x = 545,205.52
  5. Step 5: Solve for x
    x = 545,205.52/812.10
  6. Step 6: Final answer
    x = 671.35

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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.