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Finding the Fourth Proportional to 692.80, 1,040.40 and 671.20

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Solution

The fourth proportional to 692.80, 1,040.40 and 671.20 is: 1,007.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    692.80 : 1,040.40 = 671.20 : x
  2. Step 2: Convert to fraction form
    692.80/1,040.40 = 671.20/x
  3. Step 3: Cross multiply
    692.80x = 1,040.40 × 671.20
  4. Step 4: Simplify right side
    692.80x = 698,316.48
  5. Step 5: Solve for x
    x = 698,316.48/692.80
  6. Step 6: Final answer
    x = 1,007.96

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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.