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Finding the Fourth Proportional to 920.39, 1,380.78 and 343.25

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Solution

The fourth proportional to 920.39, 1,380.78 and 343.25 is: 514.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.39 : 1,380.78 = 343.25 : x
  2. Step 2: Convert to fraction form
    920.39/1,380.78 = 343.25/x
  3. Step 3: Cross multiply
    920.39x = 1,380.78 × 343.25
  4. Step 4: Simplify right side
    920.39x = 473,952.74
  5. Step 5: Solve for x
    x = 473,952.74/920.39
  6. Step 6: Final answer
    x = 514.95

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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.