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Finding the Fourth Proportional to 692.80, 1,039.20 and 281.80

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Solution

The fourth proportional to 692.80, 1,039.20 and 281.80 is: 422.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    692.80 : 1,039.20 = 281.80 : x
  2. Step 2: Convert to fraction form
    692.80/1,039.20 = 281.80/x
  3. Step 3: Cross multiply
    692.80x = 1,039.20 × 281.80
  4. Step 4: Simplify right side
    692.80x = 292,846.56
  5. Step 5: Solve for x
    x = 292,846.56/692.80
  6. Step 6: Final answer
    x = 422.70

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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.