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Finding the Fourth Proportional to 812.72, 1,218.72 and 379.64

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Solution

The fourth proportional to 812.72, 1,218.72 and 379.64 is: 569.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.72 : 1,218.72 = 379.64 : x
  2. Step 2: Convert to fraction form
    812.72/1,218.72 = 379.64/x
  3. Step 3: Cross multiply
    812.72x = 1,218.72 × 379.64
  4. Step 4: Simplify right side
    812.72x = 462,674.86
  5. Step 5: Solve for x
    x = 462,674.86/812.72
  6. Step 6: Final answer
    x = 569.29

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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.