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Finding the Fourth Proportional to 906.24, 1,249.20 and 643.80

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Solution

The fourth proportional to 906.24, 1,249.20 and 643.80 is: 887.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    906.24 : 1,249.20 = 643.80 : x
  2. Step 2: Convert to fraction form
    906.24/1,249.20 = 643.80/x
  3. Step 3: Cross multiply
    906.24x = 1,249.20 × 643.80
  4. Step 4: Simplify right side
    906.24x = 804,234.96
  5. Step 5: Solve for x
    x = 804,234.96/906.24
  6. Step 6: Final answer
    x = 887.44

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.