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Finding the Fourth Proportional to 692.88, 1,039.60 and 308.40

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Solution

The fourth proportional to 692.88, 1,039.60 and 308.40 is: 462.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    692.88 : 1,039.60 = 308.40 : x
  2. Step 2: Convert to fraction form
    692.88/1,039.60 = 308.40/x
  3. Step 3: Cross multiply
    692.88x = 1,039.60 × 308.40
  4. Step 4: Simplify right side
    692.88x = 320,612.64
  5. Step 5: Solve for x
    x = 320,612.64/692.88
  6. Step 6: Final answer
    x = 462.72

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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.