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Finding the Fourth Proportional to 813.20, 1,219.96 and 326.28

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Solution

The fourth proportional to 813.20, 1,219.96 and 326.28 is: 489.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.20 : 1,219.96 = 326.28 : x
  2. Step 2: Convert to fraction form
    813.20/1,219.96 = 326.28/x
  3. Step 3: Cross multiply
    813.20x = 1,219.96 × 326.28
  4. Step 4: Simplify right side
    813.20x = 398,055.13
  5. Step 5: Solve for x
    x = 398,055.13/813.20
  6. Step 6: Final answer
    x = 489.49

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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.