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Finding the Fourth Proportional to 813.56, 1,219.50 and 326.40

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Solution

The fourth proportional to 813.56, 1,219.50 and 326.40 is: 489.26

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.56 : 1,219.50 = 326.40 : x
  2. Step 2: Convert to fraction form
    813.56/1,219.50 = 326.40/x
  3. Step 3: Cross multiply
    813.56x = 1,219.50 × 326.40
  4. Step 4: Simplify right side
    813.56x = 398,044.80
  5. Step 5: Solve for x
    x = 398,044.80/813.56
  6. Step 6: Final answer
    x = 489.26

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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.