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Finding the Fourth Proportional to 813.28, 1,220.19 and 380.74

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Solution

The fourth proportional to 813.28, 1,220.19 and 380.74 is: 571.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.28 : 1,220.19 = 380.74 : x
  2. Step 2: Convert to fraction form
    813.28/1,220.19 = 380.74/x
  3. Step 3: Cross multiply
    813.28x = 1,220.19 × 380.74
  4. Step 4: Simplify right side
    813.28x = 464,575.14
  5. Step 5: Solve for x
    x = 464,575.14/813.28
  6. Step 6: Final answer
    x = 571.24

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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.