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Finding the Fourth Proportional to 812.68, 1,219.74 and 520.84

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Solution

The fourth proportional to 812.68, 1,219.74 and 520.84 is: 781.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    812.68 : 1,219.74 = 520.84 : x
  2. Step 2: Convert to fraction form
    812.68/1,219.74 = 520.84/x
  3. Step 3: Cross multiply
    812.68x = 1,219.74 × 520.84
  4. Step 4: Simplify right side
    812.68x = 635,289.38
  5. Step 5: Solve for x
    x = 635,289.38/812.68
  6. Step 6: Final answer
    x = 781.72

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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.