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Finding the Fourth Proportional to 813.47, 1,220.90 and 326.87

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Solution

The fourth proportional to 813.47, 1,220.90 and 326.87 is: 490.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.47 : 1,220.90 = 326.87 : x
  2. Step 2: Convert to fraction form
    813.47/1,220.90 = 326.87/x
  3. Step 3: Cross multiply
    813.47x = 1,220.90 × 326.87
  4. Step 4: Simplify right side
    813.47x = 399,067.84
  5. Step 5: Solve for x
    x = 399,067.84/813.47
  6. Step 6: Final answer
    x = 490.58

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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.