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Finding the Fourth Proportional to 774.85, 1,161.37 and 428.39

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Solution

The fourth proportional to 774.85, 1,161.37 and 428.39 is: 642.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    774.85 : 1,161.37 = 428.39 : x
  2. Step 2: Convert to fraction form
    774.85/1,161.37 = 428.39/x
  3. Step 3: Cross multiply
    774.85x = 1,161.37 × 428.39
  4. Step 4: Simplify right side
    774.85x = 497,517.15
  5. Step 5: Solve for x
    x = 497,517.15/774.85
  6. Step 6: Final answer
    x = 642.09

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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.